2021-07-01

Twelfth Paper: "Near-field radiative heat transfer in many-body systems"

My twelfth paper has been published! It is in volume 93, issue 2 of Reviews of Modern Physics, and an older preprint of it is available too for those who don't have access to academic journals (it is identical in content and only differs in formatting). Unlike my previous blog posts about published papers that I have written, this one will not strictly use the thousand most common words in English. This is because unlike my previous papers, which put forth novel ideas advancing the field of nanophotonics, this is a review paper that gives a broad historical scientific overview of the subject, namely, the flow of heat through light (i.e. electromagnetic (EM) fields) between objects that are typically separated by less than 1 micron (approximately 1% of the width of a typical human hair). It goes over work that other scientists have done theoretically and experimentally in this subject, and this paper in particular is divided into two main sections.

The first section, to which my PhD advisor & I made most of our contributions, is about the flow of heat via EM fields between just 2 objects. Relevant issues include choices of materials (mainly metals/conductors versus insulators), choices of shapes for objects, advances in experimental measurement techniques, advances in computational simulation techniques, and derivations of upper limits to the flow of heat via EM fields between 2 objects (mostly referring to my previous 2 papers that were the subject of the following linked blog post).

The second section, which constitutes the bulk of the paper, is about the flow of heat via EM fields among more than 2 objects. Relevant issues include changes in temperature over time in objects that are very small compared to their separations, the fact that the heat flow among more than 2 objects involves very complicated interactions among them, the fact that material properties could depend on temperature so there could be many possible sets of object temperatures where heat flows but temperatures don't change, heat flow via EM fields over distances longer than 1 micron, applications of heat flow via EM fields to microscopy techniques, heat flow via EM fields in materials that can be attracted to permanent magnets, and applications of heat flow via EM fields to engineer new devices.

2021-05-17

Manually Creating a Rudimentary Searchable Image Tagging System

This post is the third in a series of three posts about some changes I have been making in my personal life with respect to how I interact with online social media platforms. When I published the second post in this series, I was on the lookout for secure privacy-respecting cloud storage services. As of this post, I still haven't committed to a specific service. One of my requirements has been that the service should allow me to share certain files or folders securely with others. Unfortunately, unless I use a service like Google Drive which has just as little respect for data privacy as Facebook does, it isn't clear how I can easily tag images with details about people, location, and other comments in a way that I or others can easily search. My proposed solution, involving BASH scripts, is far from perfect, it is very much a work in progress, and it is arguably somewhat specific to my particular situation. Follow the jump to see more details.

2021-02-15

Copyright, Police Interactions, Transparency, and Corporate Dependence

On the one hand, my beliefs about police behavior & copyright law are such that this behavior disappoints me on both fronts (as I believe this is a gross abuse of the spirit of copyright law and of trust in police officers), but on the other hand, I can't help but appreciate the ingenuity of this "solution" to the "problem" of being recorded. Additionally, it is worth noting that the main instance of this happening as described in this story is in a police station, where it can be argued that police departments could rightfully enforce rules against using cell phones; that said, the story also mentions other instances of this happening in outdoor public spaces. In any case, beyond these issues, this story has raised several broader questions in my mind, which I list below, and which I do not intend to be merely rhetorical.

1. Would police officers be fined for broadcasting such music as a "public performance" in an unauthorized way?
2. Should this motivate an alliance between groups aiming to reform police departments & groups aiming to reform copyright laws?
3. Should this motivate greater use of the site Wikileaks or other existing sites, or creation of a similar site, as a well-known not-for-profit repository to document police abuses (instead of relying on for-profit platforms that might zealously enforce copyright laws)?
4. What should be the mechanism for determining which videos of police officers get publicized, in order to ensure that trivial misunderstandings don't get blown out of proportion at the expense of the livelihood of the police officer?

There are certainly many other questions that could be asked about this issue going forward. In any case, it is unfortunate that enforcement of copyright laws is being twisted in this way, but it will be interesting to see how similar cases develop in the future.

2021-01-29

My Time at the 2021 TRB Annual Meeting

This is a quick update from my attendance of the 2021 Transportation Research Board (TRB) Annual Meeting. The conference was held in a fully online format, and as a result, events were spread over the entire month, with the first & second weeks being filled with committee meetings, and the third & fourth weeks being filled with research presentations & workshops. This was my first time attending this particular conference, and it was my first time attending a conference of this size in the field of transportation since switching into this field. That said, I knew going in that certain aspects, like networking, might feel less satisfying compared to what they would have been if this conference had happened in person in normal circumstances.

I really enjoyed the committee meeting about the transportation needs of people with disabilities, and the later presentation session about the same subject, as those are among my primary research topics right now. I also really enjoyed the workshop about the history & future of road pricing, precisely because that topic is only tangentially related to my research interests, so it was fun to think about these issues that I wouldn't normally think about. Plus, in all of those sessions, I was able to meet people and expand my professional network to some degree.

Of course, the networking aspect fell far short of what I would have expected for normal circumstances, but that wasn't too surprising. More disappointing was that the last week of this conference was plagued by technical difficulties that led to me missing several sessions that I wanted to attend. In particular, the website was designed quite badly, as it often didn't load correctly, and when it did load, it was often quite difficult to navigate to the desired sessions (as it was set up to "mimic" the "spatial layout" of a convention center). Furthermore, although setting up poster sessions as a series of chat rooms may have seemed like a good idea at first, it ended up being quite frustrating to use in practice (when it worked at all), so I felt rather discouraged from signing up for further sessions.

Overall, I'm glad to have attended the committee meetings, and while I generally enjoyed the research presentation sessions that I did attend, I was rather frustrated by how this conference was rife with technical difficulties. I hope this will be a lesson for future online conferences, and I hope too that progress with vaccines against this coronavirus will mean that in-person conferences can return soon enough. (Please note that I have no expertise in epidemiology, virology, or vaccine development, so I cannot claim to prognosticate on this matter.)

Unrelated to this, please note that the public Facebook & Twitter pages for this blog have been deleted. This is because of my unhappiness with those companies' recent actions and my desire to migrate away from those platforms. Of course, this blog will continue to be published here until further notice, and it is still possible to sign up for an email subscription for new posts on this blog.

2020-12-31

Book Review: "These Truths" by Jill Lepore

I find it appropriate that to close a year that has been marked by personal highs & lows and by so much national political tumult, despair, and existential questioning, I should read the book These Truths by Jill Lepore. This is a book that I got as a birthday gift from my family within 12 months of the publication of this book, but I didn't get around to reading it until these winter holidays because I didn't want my busy schedule at work to lead me to start reading it and never finish, and because in truth I was intimidated by its length & subject matter to start it during the summer (even though I had a lot of time before starting my new job in the fall). As discussed in the preface, the book aims to be a comprehensive political history of the US, starting with the explorations & conquests by Christopher Columbus and then moving mostly chronologically forward from there, and frames this history with the overarching question of the extent to which the US has lived up to its founding ideals over the centuries. The author makes clear that the focus on political history, in conjunction of the length of the book, will require lessening focus from military & cultural history, but I felt that aspects of military & cultural history were adequately covered to support the main arguments, and I didn't feel like I missed those things so much. The author puts forth the ideal that history should be a form of inquiry that goes beyond record-keeping and her hope to be neither blindly praising nor blindly disparaging of the US, while acknowledging that her prioritization of available written records will bias the discussion toward the narrative told by people in power.

The book is rather long, spanning more than 800 pages (in the original hardbound edition) from the preface through 16 chapters and the epilogue. However, as this book is for laypeople as opposed to scholars (the latter exemplified by the book The Invention of Science by David Wootton, which I have reviewed here), the font is a little larger and has generous spacing, making it easier to read. Furthermore, the content of the writing itself flows smoothly, and this is a very engaging read. Thus, I was able to finish the book faster than I originally anticipated. Also, I initially wondered whether such a long book would be useful, because I usually like to seriously grapple with the ideas presented in a book like this, and I envisioned that every page of this book would be so chock-full of ideas that it would be too long; however, as I came to see that the narrative was a bit more fast-paced as opposed to dense, my concerns were allayed.

As I have understood, the main points of this book are as follows. In the opening statement of the Declaration of Independence, "We hold these truths to be self-evident that all men are created equal", there have been endless debates about who "we" are and to which "men" these "truths" should apply. The questions about "we" and "men" have been seen from the beginning through the conflicts about slavery and about the treatment of indigenous tribes, immigrants, and women, and in disputes since then. The questions about "truths" have been seen relatively more recently, since the 1890s, with the rise of political consultants who aim to shape public opinion to their own ends even if such actions lead to divisions that destabilize the country and lead to rejections of notions of objectivity; the author makes this point clear, drawing a straight line from the political consultants of the 1890s to the pollsters of the 1930s to the misguided idealistic computational social scientists of the 1960s to the cynical conservative political strategists of the 1970s to the conservative media personalities of the 1990s to companies like Facebook in the 2010s. Initially, I thought these points could have been made in a better way to form a more coherent narrative through the book. However, I am now more convinced by the book that further reduction of these ideas into a narrative that seems too neat would do a disservice to the complexity and dynamism of US history.

Although the author aims to stay ideologically neutral, it is clear that she writes from a more liberal perspective. This is of course obvious from the central thesis, framing issues of race, gender, and class as central to understanding US history, but it also becomes clear at various points through the text in which the author decries liberal electoral losses or things like that. While the author doesn't hesitate to criticize liberals for hyperbolically overreacting to certain conservative beliefs or public figures or for going so deep into identity politics as to reject the very notion of objectivity, the author's criticism of conservative politicians since the 1950s is more pointed, explicitly casting many such politicians & movement leaders as acting cynically even though many liberal politicians, movement leaders, and political consultants have acted in similarly hypocritical & cynical ways (giving the example of how many consultants for the Obama campaign have been hypocritical in their denunciations of Republican corruption & profit); perhaps it is true that since the 1960s, conservative politicians, movement leaders, and political consultants have behaved more cynically (in frequency and intensity) than their liberal counterparts, and I certainly learned a lot about how extensive Nixon's cynicism was, how early he developed such cynical instincts, and how much it influenced the Republican Party after his presidency, but I would still have preferred to see explicit characterizations as appropriate of certain liberal political actions as cynical. At the same time, the author's moderate stance on racial issues, decrying the ways that conservatives in the 1980s denounced "welfare queens" and the epidemic of police brutality against black people that only became broadly visible beyond black people in the 2010s while also decrying the ways that liberals sanctimoniously call conservatives racist buffoons and the splitting of racial justice movements into racial factionalism via identity politics, liberal stance on gender issues, decrying the ways that women were stymied by men in power in the quest for equality while also looking skeptically upon women who wanted to be free from male society altogether, and apparently progressive stance on economic issues, looking for real antitrust action as well as welfare, seems to align in many ways with my views; I don't know if that is due to real alignment or if that is because people of different political persuasions can feel like they align with the author, because the latter would be an act of genius on the part of the author, and in any case, it all adds up to a striking criticism of liberal politics from the 1950s onward (and especially in the 1990s).

This book illustrates how US history rhymes, even if it doesn't repeat exactly. I found myself surprised at many junctures to see how even in the 19th and early 20th centuries, so many of the debates about the nature of facts, polling, partisanship, economic inequality, civil rights, and things like that are echoed in current affairs. For example, I was surprised to see how so many court cases involving the Fourteenth Amendment in the 1870s involved questions about the extent to which corporations can legally be considered to be persons, and to see how the Republican Party of the 1880s supported trickle-down theories of economics (using almost the same terminology). In this way, there were a lot of things that I learned about US history that reaffirmed my view that arguments based on history must go beyond the last 7 decades and must properly contextualize the circumstances of the last 7 decades within the full 244 years of this country's history. Plus, the author seems to have written this book in a way that makes clear to laypeople with even a passing interest in current affairs how so many past events resemble current affairs. With respect to the point about proper contextualization, the author also does a good job of avoiding common traps of simplistic conventional wisdom. For example, the author clearly shows how the supposed consensus from people watching the same TV news sources in the 1950s & 1960s was an artifact of the Cold War and of lack of racial & ideological diversity, because the first decade of the Cold War largely forced both major political parties to become essentially indistinguishable, preserved a status quo in which positions of power in politics & the media would be held by old white men, and thereby ensured in practice that any deviation from these norms would be implicitly censored. However, the author isn't perfect in this regard, and I think the author's lapses in this way could have been solved by more explicitly connecting discussions of later events to previous discussions in the book of earlier events. Using the same example as before, the author contrasts the partisan media fragmentation of the cable TV environment of the 1990s with the unified network TV environment of the 1950s but fails to connect this with the earlier discussion of why the supposed consensus of the 1950s was actually artificial to a large degree.

There are some bigger problems that I have with this book given its central thesis, and these are all about what the book doesn't discuss in sufficient detail. First, the book doesn't properly discuss the electoral college of relevance to electing the president. There are mentions of electoral shenanigans in the elections of 1796, 1800, 1876, 2000, and 2016, but given how the author clearly shows the expansion of the president's powers and the growing dysfunction of the political system at the federal level in the US, I think there should have been much more discussion of when, why, and how the electoral college shifted from an meaningful body of electors selected by state legislators to a winner-take-all (except in Maine & Nebraska) accounting of the presidential winner & congressional representation in each state. Second, there isn't much mention of Native American affairs following the ratification of the Constitution, nor of the systems of government by Native American tribes before then. Perhaps it can be argued that Native American systems of government didn't really inform and therefore weren't really relevant to the system of government laid out in the US Constitution, or that Native American affairs weren't central to US political disputes after that because those tribes' populations were already so small after the genocides & pandemics committed by & following Christopher Columbus, but this should have been made clearer. Perhaps the relatively small number of extant written records by Native Americans influenced the author's focus, as the author herself admitted could be a possible source of bias, but if the author anticipated that, then she should have consulted other Native American sources too as is evident from the Smithsonian National Museum of the American Indian in DC. Third, there could have been a much more thorough discussion of race in the context of immigration from Europe, treatment of Native Americans, and slavery: I've already read about many of these subtleties in the book The Half Has Never Been Told by Edward Baptist (which I have reviewed here), and read on Wikipedia about how even Native Americans owned black slaves, so I think at least a bit more discussion of these issues would have greatly strengthened the central thesis of this book.

Overall, I really enjoyed reading this book, and I learned a lot about US history from it, even as I felt that it reinforced some of the facts that I already learned as well as some of the views that I already held. I highly recommend this book to anyone who has even a passing interest in current affairs & US history.

2020-11-27

A Reminder about Remote White-Collar Work and Loss during this Pandemic

As always, please note that I have no expertise in public health, and please follow relevant guidelines from public health officials regarding this pandemic.

This is a short post about the effects of this pandemic on white-collar workers, although the needs of essential blue-collar & service workers during this pandemic should not be ignored either. Over the last several months, I have read many op-eds about how the huge shift to remote work for white-collar jobs may or may not last after this pandemic, and on the whole, those op-eds basically saw this shift as a giant social experiment to see how well people could work in white-collar jobs when physically separated from each other, with very little mention of the broader context of this pandemic (beyond narrow questions of hygiene & safety in offices). It was tempting for me to think about this pandemic in such abstract terms too. However, I recently experienced a death in my family due to this coronavirus, and especially as I was very close to that person, it reminded me of a more basic fact, as follows.

This coronavirus is killing many people, and it is irreparably damaging the health of many others; in turn, it is severely damaging the mental (and in some cases physical) well-being of people whose loved ones are directly affected. Thus, white-collar workers aren't simply working from home in a giant social experiment; many of them are dealing with these tragedies among their relatives & friends. Given this, even though it might be tempting for employers, managers, and supervisors to think that workers are accustomed to the situation, I hope that many of them start (if they haven't done so thus far) or continue to be empathetic to the problems that many of their workers face outside of work, giving those workers time & space as appropriate to deal with those problems; of course, many white-collar workers had to deal with caregiving responsibilities as well as illnesses among family members & friends before this pandemic, but this pandemic has drastically increased the number of such people dealing with such problems at any given time, the magnitude of such problems, and the uncertain course of such problems (as the disease itself has such an uncertain course).

2020-10-19

Book Review: "The Drunkard's Walk" by Leonard Mlodinow

There are other aspects of human behavior that this book fails to adequately capture; these may technically be beyond the scope of this book, but I think they are worth noting anyway, as they speak to larger problems with the ability of people (even those well-trained in STEM fields) to really understand probability theory. The second chapter goes over many examples of how, in the technical language of probability, given events $$A$$ and $$B$$, certain questions can be framed such that laypeople and professional specialists (particularly doctors & lawyers) fall into the trap of believing that $$\operatorname{Pr}(A \cap B) > \operatorname{Pr}(A)$$ even though the opposite is mathematically always true. However, I can already see that the phrasing of many of those questions, particularly the way that events $$A$$ & $$B$$ are juxtaposed (especially if $$B$$ is additional information that may be relevant to the assessment of $$A$$), may make people believe either that what should be interpreted as $$\operatorname{Pr}(A)$$ is actually $$\operatorname{Pr}(A \cap \neg B)$$, in which case $$\operatorname{Pr}(A \cap B) > \operatorname{Pr}(A \cap \neg B)$$ could in fact be true, or that what should be interpreted as $$\operatorname{Pr}(A \cap B)$$ is actually the conditional probability $$\operatorname{Pr}(A|B)$$, in which case $$\operatorname{Pr}(A|B) > \operatorname{Pr}(A)$$ could in fact be true. This speaks more to the way that natural human language is unsuited to the subtleties of the language of probability theory, yet rather than address these possibilities, the author again leaves the discussion there, implying disdain for people who are too stupid to know better. Another problem is that throughout the book, the author raises the question of how to determine whether a particular sequence of observations of outcomes for a process that may be random reflects a specific probability distribution model, but never clearly explains how to do this in practice, instead only giving hints about this through various examples. This is related to the question of why one may prefer an explanation based on probabilities than based on deterministic phenomena, particularly for small sample sizes. For this, I will give an example. Consider exactly 5 observations of an event, which has binary outcomes (either success or failure), for which no other observations are made, and for which in all of those 5 observations, success occurs every single time. Intuitively, laypeople might be inclined to believe that there is a deterministic cause of this, while if a probability theorist were to initially believe that this is consistent with a binomial distribution with $$(N, p) = (5, 0.6)$$ but then later revise this to $$(N, p) = (5, 0.99)$$, laypeople could reasonably wonder why this would be justified, and why the probability theorist refuses to believe in the possibility of some deterministic causal relationship. Of course, this is a contrived example, I understand why causation needs to be proved as an alternative to a null hypothesis, and I understand that probability distributions closer to uniform probabilities are favored as those that maximize entropy (which essentially means that subject to certain known constraints, the probability distribution that best reflects the state of ignorance about a system is closest to uniform), but the author does not properly explain these points. Finally, the broadest problem with this book is that the author only superficially acknowledges the issue that if every calculation in probability theory or statistics, whether of a certain event happening, a string of events being a true "hot streak", or a model fitting data correctly, is itself a probability, then the aforementioned disconnect of this language of probability from natural human language makes it difficult to translate probabilities into robust rules for deterministic (usually binary) decisions that laypeople must make; this is related to the idea that in game theory, a single person playing a single-shot game cannot play a mixed strategy, and the concept of a mixed strategy only makes sense in the context of observing a large ensemble of independent players, possibly playing repeatedly. Perhaps asking the author to address this problem is too much, but I still feel like such failures diminish the book in comparison to its hype.