unpacking solvers: streamlining complexity Solvers are advanced software tools designed to process specific mathematical programs and deliver solutions, like a linear programming solver. When juxtaposed with algorithms—which are methods crafted for distinct problems—solvers operate on a broader spectrum, targeting classes of problems rather than individual cases. This abstraction not only boosts their flexibility but also their application across industries. Solvers enable a division of labor that heightens efficiency. Industry specialists focus on refining models to encapsulate real-world complexities, while solvers handle the computational tasks....

Here’s a note that clarifies two notions in econometric that I found confusing somehow. And mid-term exam is on the way so here’s a note. playground Let ${Y_1, Y_2, \ldots, Y_n}$ be a collection of independent and identically sampled random variables out of $f(y; \theta)$, where $\theta \in \Theta$ is a (possibly unknown) parameter associated with the distribution. In general, we want to estimate $\theta$ using our samples $Y$. An estimation of $\theta$ - random variable $W$ can be expressed as $$ W = h(Y_1, \ldots, Y_n) $$...

Marianela Nunez’s rendition Kitri in The Royal Ballet’s production of Don Quixote is amazing. Kitri, if one doesn’t know, is the lead character in Don Quixote’s ballet-adjusted version. She embodies the Mediterranean dream of men: a flirtive, sexy and charismatic matured woman in her signature red dress. The first time I watched it I was in awe. After almost infinite replays I came to realize that Nela’s Kitri is by far the most nuanced classical artistic performance I’ve ever seen....

Prof. Yi Xiong’s Frontiers in Management Science Session covered a crash course on online learning and multi-armed bandits (MAB). A simple way to view MAB is to consider it as a tool to model and study online learning problems. At time $t$, a decision maker chooses an ‘action’ or arm $i_t\in \mathcal I$ ($\mathcal I$ is the known set of distributions). The chosen machine returns a random reward $r_t$ following its distribution $Q_t$....

Our Frontiers of Management Science Seminar looked into a study that grounded operational management analysis in real application: Capacity Investment in Renewable Energy Technology with Supply Intermittency: Data Granularity Matters! Hu et al., MSOM 2015 ABSTRACT We study an organization’s one-time capacity investment in a renewable energy-producing technology with supply intermittency and net metering compensation. The renewable technology can be coupled with conventional technologies to form a capacity portfolio that is used to meet stochastic demand for energy....

Take Five is a jazz standard (i.e. a jazz song that has a rich history of being interpreted and reinterpreted), first recorded in 1959 and is the third track on Time Out by the Dave Brubeck Quartet. The song is in quintuple $5/4$ time, and this is where it got its name. Channeling my inner Dave Brubeck with a ‘Take Five’ moment, I am taking a short five-day breather to recharge and find some fresh tunes....

Just imagine how much cool I’d be in summer! In Summer, Frozen (2013). Summer holds a cherished place in the hearts of Chinese people. It’s a time of graduation, moving onto new chapters in life, accompanied by the humming of hot air and cool breezes, and the taste of iced watermelon. My heart skips a beat whenever I recall those memories—the midnight walks along the Thames in London, driving along Big Sur, or even just buying silly cat dolls at home with my dad....

Summer is on the way! At least for us here in Shanghai. A few days ago, I stumbled upon “South of the Border” – a collaboration between Ed Sheeran, Camila Cabello, and Cardi B – and it’s been stuck in my head ever since. The song exudes the typical Ed Sheeran bar-dance-music vibe, but with a twist. Camila adds a dash of Cuban flavor, while Cardi B brings her characteristic playfulness to the mix....

Following yesterday, the second paper I’d recommend is Carvalho et al. Penalties and Rewards for Fair Learning in Paired Kidney Exchange Programs (WINE2023). The paper took a data-driven approach and tested its method on Canadian Kidney Exchange program’s data. It established a dynamic (over time) kidney exchange model so as to take in consideration of some aspects missed by myopic naive matching schemes. They developed a novel learning approach to update the weights of the vertices so as to improve equity as well as efficiency....

Looking at two-sided market literatures so as to motivate one of my recently launched project, here’s a brief reading write-up of two papers. Starting with the first one: Ashlagi et al. On Matching and Thickness in Heterogeneous Dynamic Markets (OR2019). kidney exchange 101 Before diving into the paper, here’s how kidney exchange actually works. the concept of “exchange” Kidney transplantation is essential for patients with late-stage renal failure. While a healthy individual can donate one of their kidneys to their loved ones, often the donor is incompatible with the intended recipient....