Educational Background

My story, perhaps, can be told to begin with my college years, which was at Institut Teknologi Sepuluh Nopember (ITS) Surabaya, Indonesia, majoring in structural engineering, from 2013 to 2017. From the beginning of the college, I had always been motivated to be majoring in structural engineering, and it culminated in my undergraduate thesis on the design of a cable-stayed bridge structure. You can visit my undergraduate thesis here.

However, at some points after graduating from the college, I questioned my past choice of taking civil engineering, since it later became a regret in my life. I eventually no longer had passion in this subject. I have evolved, my mindset has.

Work Experience

After earning a Bachelor of Applied Science (B.A.S.) in 2017, I worked at various different positions with different skills required. I was a civil engineer at a state-owned construction company in my country for a few months—March 2018 to September 2018. Then I moved to a different but similar company, also as a civil engineer but this one assigned at the HQ where I mostly dealt with bidding processes—February 2019 to September 2020. The main task I undertook at this position was preparing civil engineering documents, including developing scheduling plans, constuction methodoligical plans and pre-construction engineering assessment for special cases such as analysing and designing the reinforcement for deep excavations, etc.

I started my freelance activity in early 2021 during the pandemic. Most of my freelance works were structural engineering designs and evaluations. Some of my past freelance works include structural designs and analyses of a three-storey dormitory building, a three-storey medical storage building, and some three-storey residential houses, and also structural evaluations of a three-storey building renovated into a cafe and industrial warehouses for solar PV installations.

In October 2022, I returned to a full-time position as a civil engineer at the same company but assigned to their EPC division. I was assigned for a massive smelter project. In this project, I was mainly tasked to guide the consulting vendors for the design and analysis of industrial buildings and infrastructures. Other tasks included developing testing procedures for field testing such as static load tests (SLT) for pile foundations as well as analysing and inferring conclusions from the results, solving specific problems such the structural implications on the functionality change of some buildings due to owner's requests for design alterations or due to the site's challenging conditions. I was also tasked to directly produce the structural reports for several buildings such as chemical store room, and several infrastructures such as pipe bridges and pipe racks. Then, from March 2024 to September 2024, I was assigned for another project on the construction of a port for fuel terminal. In this project, the tasks assigned to me were almost the same with ones in the previous project. In addition, I was highly involved in controlling the material take off (MTO) for the port construction.

I am currently working as a freelance AI Training Specialist and a part-time research mathematician and scientist. I am currently contributing as a co-researcher in a research project focusing on optimization of concreting cycle in a construction project, led by a researcher at a top university in Indonesia. We develop a novel combinatoric-based theoretical framework to model the concrete-sequencing problem incorporating set theory, number theory and max-plus algebra. We initially focused only with the specific application for the concrete sequencing problem. My mathematical instinct signalled to abstract and axiomatize this framework, which eventually gave birth to the theory of Combinatorial Grid Sequencing (CGS), a combinatorial theory to model and solve a restricted class of more general combinatorial problems. Now CGS is no longer a specific framework only for the concrete sequencing problem, but also for any mathematics combinatorial problem satisfying a certain characteristic coined as a CGS problem. With this condition, we divided our initial single paper into two separate papers. The first one contains the theory of CGS as a purely mathematical theory. The second one focuses on the initial applied problem where we apply CGS to model scenarios of concrete sequencing, and eventually for the optimization. We build an objective function for the optimization where the CGS functional—a certain functional on $\mathbb{Z}_{\max}$—helps find the total duration of the concrete sequencing. This project also receives grants from the university. This research has been one of the most exciting and ambitious projects so far in my independent research career.

Research Experience

I began my journey in scientific research in mid 2022, as a consequence of my self-directed exploration in mathematics—which to be narrated as you keep reading this page. My first research project was interdisciplinary research intersecting mathematics and structural engineering. Inspired by monumental works such as Kolmogorov's in axiomatizing probability and Shanon's in information theory, I had an idea of providing a rigorous and formal treatment on the theory of pure bending structure incorporating measure theory in pure mathematics, started with a reinforced concrete beam structure. The central notion in my idea is that we can model the cross section of such a pure bending structure as a measurable space. The stress occuring on the surface of the cross section can then be treated as a measurable function on that measurable space. Eventually, the force on an arbitrary measurable region on the surface of the cross section can be obtained from the Lebesgue integral of the stress measurable function over that region. Likewise, by introducing another measurable function obtained via a pseudometric space on the measurable space, the ultimate moment can be obtained from the Lebesgue integral of the stress measurable function multiplied with the newly introduced measurable function over the entire space. I also proved the conventional nominal moment equation for reinforced concrete beam as a particular implication of my theory. The envisioned importance of this theory is that one can compute the moment capacity of a bending structure with a general well-behaved material with an aribtrary cross-sectional shape.

My second research project was an intersection of mathematics and geotechnical engineering. Specifically, I propose a novel approach for interpreting the result of a static load test (SLT) by incorporating a concept in mathematical analysis: Lipschitz continuity. First, we develeop a differential equation representing the force-settlement relationship from the SLT data as a continuous approximation of the relationship. The solution of the differential equation is given by a continuous function $S: \mathbb{R}^+ \to \mathbb{R}^+$. Given some $R > 0$, we can find some connected bounded set $Q_u \subseteq \mathbb{R}^+$ such that $S$ is locally Lipschitz on $Q_u$, i.e., $S \big|_{Q_u}: Q_u \to \mathbb{R}^+$ is Lipschitz. And we define the critical force of the pile as $$ q_u := \sup{Q_u} \,. $$ This theory, when compared with existing theory, offers several advantages. First, it is highly and much more rigorous than the existing theories. Second, this theory is formal and axiomatized, and important properties are theoretically guaranteed as theorem while the existing theories are heuristic. Third, the result is mathematically objective as it relies on the intrinsic mathematical structure of the SLT result, rather than subjective and outright empirical observation on the data as employed in the existing theories.

I also did some other research on more trivial topics—which, in my humble opinion, are not quite high level, such as; estimating the deflection of bending concrete structure using Euler-Bernoulli beam theory based on the approximate moment formulae provided by ACI 318-19, extrapolating Cone Penetration Test (CPT) data by incorporating time series technique with a machine learning implementation, developing a machine learning predictive model for concrete compresive strength, developing my owned customized machine learning-based time series algorithm, and analysing market demand and sales forecast of a coffee shop by incorporating measure and probability theory as the theoretical framework and machine learning as the computational technique. Some of these works may offer some degree of novelty and uniqueness. Therefore, there are still plenty of chances for me to revisit these projects for refinements in the future.

My third original research project was an intersection of mathematics and environmental science. I propose a set of rigorous notions which are very helpful for meticulous analyses on the historical greenhouse gas (GHG) emissions of countries world wide. In this research, borrowing from the formal notions in mathematical analysis and probability theory, I introduced several notions in GHG emissions including; continuous emission process (CEP), discrete emission process (DEP), historical upper bound emission (HUBE), historical peak emission (HPE), rapid growing emission (RGE), rapid shrinking emission (RSE), pivotal periods (Piviods), historical expected growth rate (HEGR) and conditional historical bound space (CHBS). I also demonstrated the use of these notions on a historical GHG emissions dataset, and pinpointing top GHG emitting countries in the world.

My fourth original research is in mathematical optimization. Having collaborated with a mathematician at Institut Teknologi Sepuluh Nopember, we develop a novel optimization algorithm, coined as the Directional Adaptive Metric Sampling Minimal Expected Loss (DAMSMEL). DAMSMEL is a gradient-free optimizer, intended as an alternative to the family of gradient-base optimizers (GBOs). The notable advantage of DAMSMEL over GBOs is that DAMSMEL does not require computing the gradient of the objective function—effectively reducing the process, and DAMSMEL can escape local minima and eventually converges to the global minimum under the right condition whereas GBOs are naturally stuck in local minima. We have empirically tested DAMSMEL on several problems: finding the global minima of a convex objective function, where DAMSMEL matches the GBOs performance; finding the global minima of a nonconvex objective function, where DAMSMEL outperformes GBOs; and implementing DAMSMEL as a machine learning model for predicting the compresive strength of concrete structure, where DAMSMEL matches both linear regression and SGD models. The main drawback of DAMSMEL, however, is the time complexity, which grows very large as the number of sampling, dimension and steps in the hyperparameter are getting larger. It is necessary to assert that DAMSMEL is not a heuristic algorithm, since its construction is grounded in functional analysis and we work on theoretical properties of DAMSMEL. Notably, I have successfully proven the condition for convex convergence of DAMSMEL. We are still further investigating the functional analysis properties of DAMSMEL such as fixed point property and its potential role as a bounded operator.

My fifth research project is CGS, in a collaboration with a researcher at the Department of Civil and Environmental Engineering, Gajah Mada University. CGS is the second highly mathematical research detached from the real-world problem after DAMSMEL, which still serves the real-world purpose. This is my first experience with max-plus algebra too, and I am very grateful to already have a background in abstract algebra before, making the process much easier. CGS is also my first time working on combinatorics and number theory in research capacity. There are exciting properties and theorems in the theory of CGS. My favourite ones are the bijectivity and inverse theorems of an ordering map called the Lexicographic Ordering (LO). I also discovered three number theoretic identities involving the floor function presented as a lemma, which are required to prove the bijectivity and inverse theorems. Now I am working independently exploring further about these identities, and I plan to write another pure number theory paper about this topic. I discovered a very interesting mathematical phenomenon with these identities: a map constructed with the first identity forms a global attractor that absorbs all integers into a global fixed-point.

Mathematics Journey

Mathematics cannot be separated from my story—it is the most beautiful and elegant abstract creation I’ve ever encountered, and a passion I hold dear. My journey into mathematics began in late 2018, sparked by a self-directed attempt to study the finite element method (FEM). However, I quickly realized that I was missing some essential mathematical foundations that prevented me from fully grasping the subject. This gap led me to explore deeper into mathematics—calculus and differential equations.

That self-directed exploration soon went astray—but in the best way. As the beauty of mathematics unfolded before me, it completely captured my attention, pulling me far beyond my original goal. I eventually reoriented myself: I would pursue mathematics not as a means, but as an end in itself.

I delved into a wide range of mathematical topics—from foundations and abstract pure math to applied mathematics. I spent several months building a strong foundation in set theory and first-order logic. One concept that particularly blew my mind was the hierarchy of infinities: that some infinite sets are strictly larger than others. Another was the famous Russell's paradox, which can be illustrated by the following story:

Imagine a city with a single barber. This barber has a very specific rule: he shaves exactly those men in the city who do not shave themselves. Now, let me ask: Does the barber shave himself?
If the barber shaves himself, then according to his rule, he must not shave himself. But if he does not shave himself, then he must shave himself. This leads to a contradiction: the barber shaves himself if and only if he does not shave himself.

Russell's paradox is just one of several motivations for refining the foundations of set theory. One of the most prominent efforts in this direction is the Zermelo-Fraenkel set theory with the Axiom of Choice (ZFC), within which such paradoxes are avoided by careful axiomatization. Subsequent attempts of refinements followed the framework of axiomatization, generally, known as an axiomatic set theory. Later, I encountered another mind-bending result: Gödel’s Incompleteness Theorems , which reveal fundamental limits of formal systems and mathematics itself.

The most enchanting part of my journey, however, came with my first exposure to group theory and abstract algebra as a whole. For me, abstract algebra, which can simply be described as the study of symmetries, is a pure beauty in mathematics. Furthermore, I delved deeper into pure mathematics and encountered the more abstract sides of mathematics in subjects like measure theory, functional analysis and topology. In particular, topology studies properties of spaces which are invariant under continuous deformation. While functional analysis can be described as a study on abstract vector spaces related to analysis properties such as convergence, completeness and operators between vector spaces.

I have set a direction for myself to further specialize in both topology and functional analysis. I aspire to contribute in these fields, pushing the fields into another frontier, and bringing them back into fruitful real-world applications. My works up to this point have been, accidentally, walking the path of Hilbert's sixth problem. The legendary German mathematician David Hilbert proposed 23 problems in 1900 that were expected to redirect mathematics in the 20th century. The sixth one, he proposed to axiomatize physics after he successfully axiomatized geometry earlier. Two first branches of physics he mentioned at the time were probabilities and mechanics. Andrey Kolmogorov successfully closed the problem for probability where he utilized measure theory to describe everything about probability. The work of Albert Einstein in General Relativity closely intersected with this problem; Einstein corresponded extensively with Hilbert and Emmy Noether in the process, which ultimately led Hilbert to derive the field equations of General Relativity from an axiomatic foundation as a direct contribution to the mechanics branch. Mirroring this philosophy, my own work originates in engineering; by abstracting these practical problems into rigorous mathematical frameworks, I have found that the resulting theories possess an inherent, standalone beauty, yet they persistently loop back to yield powerful new tools for solving the original engineering challenges.