Evidence, methods, and operating insight for decisions that must work in the field.
The ultra-high-rise condo pre-sales market in Ho Chi Minh City. A showdown between an intuition-driven ace salesman and a data-driven rookie. This novel format explains how the EXAWin Bayesian engine becomes a tool for victory in the Southeast Asian real estate sales competition. Part 1: The calm before the storm — two salesmen in Saigon.
The conclusion of the 480-unit condo pre-sales war in Ho Chi Minh City. President Phan's contract, Tuấn's awakening, and the turnaround led by Park Jun-hyuk's EXAWin. The showdown between intuition and data finally reaches its conclusion.
This story depicts the process of resolving chronic chaos on the manufacturing floor through EXA's advanced Bayesian algorithm and production scheduling engine. Moving away from the indiscriminate push-style production methods of the past, it introduces data-driven simulation and backward scheduling to precisely control process bottlenecks. Through real-time data learning, the system sets dynamic buffers and reorders priorities toward optimizing schedules based on bottleneck process capability for due-date compliance rather than simple utilization. As a result, by suppressing unnecessary WIP and securing protective capacity, the factory undergoes an innovative transformation in which profitability and due-date hit rate rise even while physical machine operating time decreases. It shows the completed form of a demand-driven Pull production system realized by combining human intuition with cold data computation.
The EXA Bayesian Engine calculated win probabilities, but its precision depended on manually configured initial parameters. When 100 historical deals accumulated, the engine was ready to evolve on its own. Grid Search, MCMC Ensemble Sampling, and Cross-Validation — three mathematical pillars working in concert to find optimal parameters. Told as a story.
How do you find the 'optimal' among 3,240 parameter combinations? Grid Search performs an exhaustive scan, and Youden's J Index finds the balance point between Sensitivity and Specificity. The mathematical principles behind data-driven tuning of sales stage weights (T) and signal sensitivity (k) — the first pillar of Auto-Tuner — explained with business context.
If Grid Search found the 'tallest hill,' the MCMC Ensemble Sampler is the process by which 256 explorers reach consensus that 'the height is correct.' The mathematical principles behind Emcee's affine-invariant walkers, R̂ convergence diagnostics, HDI 95% credible intervals, 5-Fold cross-validation, and Signal Lift analysis — explained with business context.
This is the first article in a technical explanation series identifying the operating principles of the EXA engine, which played a major role in the novel-style series [BA03 On-Time Material Inbound: Bayesian MCMC]. Since this series covers Mixture Distributions and MCMC (Markov Chain Monte Carlo) Gibbs Sampling—which are advanced techniques in Bayesian inference—the content may be deep and the calculation process somewhat complex. Therefore, we intend to approach this in a detailed, step-by-step manner to make it as digestible as possible, and it is expected to be a fairly long journey. We recommend reading the original novel first to understand the overall context. Furthermore, as Bayesian theory expands its concepts incrementally, reviewing the episodes and mathematical explanations of BA01 and BA02 beforehand will be much more helpful in grasping this content. The preceding mathematical concepts and logic are being carried forward.
BA03. [On-Time Material Inbound: Bayesian MCMC] The Real Game in Business is the Fight Against Uncertainty
