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Revised Scope: Design and Implementation of a Portable Bus-Powered Dual-Mono USB-C DAC/AMP on the XMOS XU208 Platform
(German-Mongolian Institute for Resources and Technology (GMIT), 2026) Gal, Unubold; Supervisor 1: Kim Young Suk, PhD.; Supervisor 2: Nikita Abramov
This thesis documents the design and implementation of a portable, bus-powered USB-C digital-to-analog converter and headphone amplifier (DAC/AMP) on a 4-layer mixed-signal PCB. A review of the commercial portable DAC/AMP market shows that budget and mid-range devices typically rely on single-stereo DAC architectures, PLL-derived clocks and limited power distribution, while XMOS XU208-based designs have so far been restricted to desktop devices.
The design evolved through two architectures and three revisions. Version 1, a desktop architecture, produced simulation work including a MOSFET-based capacitance multiplier achieving -112.12 dB power-rail SNR. Version 2 initially used the CT7601CR MCU, which was replaced by the open-source XMOS XU208 USB audio processor due to its closed firmware ecosystem. The final design implements a true dual-mono architecture with two independent CS43131 DAC/AMP chips, three independent crystal oscillators for jitter-free master clock distribution, and a cascaded power distribution network (TPS7A9101, LT3045 and SGM2036 regulators) that isolates the analog supply chain from USB VBUS noise. It provides both 3.5 mm single-ended and 4.4 mm balanced outputs within the USB 2.0 500 mA current budget.
Design decisions were based on manufacturer design guides, datasheets and established EMC literature, and a failure mode and effects analysis (FMEA) was performed on the final revision. The fabricated board is ready for assembly, and a three-phase verification methodology (power-on, firmware bring-up and audio performance measurement) is defined to validate the theoretical performance in hardware.
Coordinate Measuring Robotic Arm
(German-Mongolian Institute for Resources and Technology (GMIT), 2026) Sodbayr, Amarjargal; Supervisor 1: Prof. Young Suk Kim; Supervisor 2: Prof. Sungchil Lee
This thesis presents the design, development, and experimental validation of a coordinate measuring arm intended for educational and small-scale engineering applications. Conventional coordinate measuring machines (CMMs) are expensive and unsuitable for resource-limited environments; therefore, this work proposes an accessible alternative based on three-joint articulated arm mechanics, absolute rotary encoders, and RS485 Modbus RTU communication. The mechanical structure was designed using Autodesk Inventor and fabricated through fused deposition modelling (FDM) 3D printing. A Python-based software application was developed to acquire encoder data, compute end-effector coordinates using planar forward kinematics, and reconstruct basic geometric shapes including lines, triangles, and circles. A graphical user interface provides real-time visualization of the arm configuration and measurement results. Calibration methods including offset correction and global scaling were implemented to reduce systematic errors. Experimental validation demonstrated that the system achieves line measurement accuracy within ±2%, circle measurement error below 3.3%, and reasonable geometric fidelity for triangular shapes. These results confirm the feasibility of developing functional coordinate measurement capability using low-cost, readily available components.
Numerical Analysis of Heat Transfer and Thermal Efficiency in a Traditional Mongolian Ger: Influence of Chimney Geometry
(German-Mongolian Institute for Resources and Technology (GMIT), 2026) Molomjamts, Oyunjargal; Supervisor 1: Sungchil Lee, Ph.D, P.E; Supervisor 2: Kim Young Suk, Ph.D
This thesis presents a comparative computational fluid dynamics (CFD) investigation into the heat transfer performance of chimney geometries used in Mongolian traditional ger (yurt) heating systems. Using ANSYS Fluent 25 with a two-dimensional axisymmetric transient model incorporating the SST k-ω turbulence model and the Discrete Ordinates radiation model, ten simulation cases were conducted across three categories of geometric variation: chimney inner diameter (0.08 m to 0.12 m), number of external horizontal annular fins (5, 7, and 9), and coaxial cylindrical extension (0.2 m and 0.25 m). The model was validated against experimental field measurements of a coal-heated ger reported by Purev et al. (1) in 2022, achieving agreement within 0.79% at the reference monitoring point. Results for the diameter variation indicate a irregular relationship between chimney diameter and indoor temperature, with a minimum observed at 0.10 m and recovery at 0.12 m due to recirculation effects and increased stove radiation. Chimney wall heat flux increased consistently with diameter, while draft velocity decreased. For the annular fin configurations, contrary to classical fin theory, all finned cases reduced total heat transfer by approximately 60% relative to the bare cylinder baseline. This is attributed to the perpendicular orientation of horizontal fins obstructing buoyancy-driven natural convection and suppressing internal draft through a coupled thermal-fluid feedback mechanism. For the coaxial cylindrical extension, the 0.2 m diameter extension achieved a 16.9% improvement in total convective heat output over the baseline by adding sufficient dissipating surface area, while the 0.25 m extension reduced output by 29.0% due to excessive draft suppression. These results provide the first geometry-based numerical design investigation for ger chimneys, suggesting that the current MASM standard diameter of 0.10 m is thermally suboptimal (though, at the same time it could be the best configuration in the context of quality of indoor air) and that a well-sized coaxial extension represents the most promising configuration for enhancing ger heating efficiency.
Design and Simulation of a Temperature-Controlled Ventilation System for a Greenhouse
(German-Mongolian Institute for Resources and Technology (GMIT), 2026) Boldbaatar, Erdenejargal; Supervisor 1: Prof. Odbileg Norov; Supervisor 2: PhD Kim Young Suk
This thesis presents the engineering design of a temperature-controlled forced ventilation greenhouse system adapted to the continental semi-arid climate of Ulaanbaatar, Mongolia. The study follows a dual methodology: a parametric three-dimensional structural model developed in Autodesk Inventor 2026, and a discrete-time PID temperature controller implemented and verified within the Wokwi embedded systems simulator. A thermal load analysis, using a peak solar irradiance of 800 W/m² and an ambient design temperature of 35°C, established a peak solar heat gain of 58.3 kW for a single-span greenhouse of 189 m³ internal volume clad in 16 mm twin-wall polycarbonate. The resulting design ventilation rate of 30 air changes per hour corresponds to a volumetric flow of 1.57 m³/s, delivered by a North-wall intake fan through a three-branch perforated PVC duct network. Perforation spacing is tapered from 300 mm at the inlet to 200 mm at the capped end, following the Teitel hydraulic pressure-compensation model, to promote uniform jet discharge across the full branch length. The PID controller was tuned using the Ziegler-Nichols closed-loop method, yielding gains of Kp = 4.8, Ki = 0.16, and Kd = 36.0. Four simulation scenarios step response, setpoint tracking, disturbance rejection, and anti-windup verification confirmed all twelve specified control behaviors, including proportional fan modulation, integral setpoint convergence, derivative disturbance response, anti-windup clamping, and independent safety cutoff at 45°C. The thesis explicitly acknowledges that CFD spatial validation and physical hardware testing constitute the primary recommended continuation of this work.
Development of Control System of Autonomous Cleaning Robot for Large Indoor Area
(German-Mongolian Institute for Resources and Technology (GMIT), 2026) Tamir, Telmen; Supervisor 1: Ph.D. N. Odbileg; Supervisor 2: Ph.D. Youngsuk Kim
This thesis presents the development and simulation-based validation of a control system for an autonomous cleaning robot designed for large indoor areas. The selected test environment is the main hall and corridor area of the GMIT first floor, which includes long corridors, curved boundaries, irregular wall geometry, and fixed internal obstacles representing a realistic and navigationally complex indoor space.
The system is structured as a two-stage simulation workflow implemented in CoppeliaSim EDU and MATLAB R2025b. In the first stage, a Pioneer P3DX differential-drive robot equipped with a 360-degree LiDAR sensor assembly performs boundary-following exploration, generating an occupancy grid map that is exported for external processing. In the second stage, MATLAB processes the raw map through noise removal, free-space extraction, obstacle inflation, and edge polyline extraction, then generates a complete cleaning mission combining boundary edge-cleaning paths, interior zig-zag coverage paths, safe transition routes, and a return-to-start path. The mission is executed in CoppeliaSim using a pure pursuit path tracking controller, with cleaning coverage tracked continuously throughout execution.
The system achieved a final cleaning coverage of 99.4 percent, exceeding the predefined success threshold of 95 percent. This result was obtained under ideal simulation conditions in which the map and execution environment are identical and localization error is absent. These conditions represent an upper bound on expected performance, and physical deployment would introduce additional factors including sensor noise, odometry drift, and environmental changes not captured in simulation. A proposed hardware deployment architecture for transferring the developed system to a physical Roborock-based platform is included as a foundation for future implementation and validation.