https://doi.org/10.5207/JIEIE.2026.40.5.313

Hyeran Kang ; An-Seop Choi

In this study, an adaptive lighting operation strategy for UAV-based nighttime maritime search and rescue under sea fog conditions was proposed based on the operational stages of the IAMSAR framework. The proposed strategy consists of environmental condition assessment, search, identification, and rescue support stages. Visible (VIS) and 850 nm near-infrared (NIR) lighting are selectively employed according to the operational stage and environmental conditions. The lighting beam angle is determined considering the camera field of view, target distance, and required illumination area, while the luminous flux or radiant output is estimated considering atmospheric attenuation. An operational example for a person-overboard search under nighttime sea fog conditions was presented to demonstrate the estimation of lighting parameters at each stage. The proposed strategy provides a basis for the design and operation of adaptive UAV lighting systems for nighttime maritime search and rescue.

https://doi.org/10.5207/JIEIE.2026.40.5.321

Intae Kim ; Meeryoung Cho ; Jun Heo

With the recent proliferation of smart buildings and zero-energy buildings, the introduction of AI-based autonomous control systems is accelerating. However, issues are arising where AI automatic control, aimed at reducing building energy consumption, is instead compromising occupant comfort and decreasing user satisfaction. Accordingly, this paper derives evaluation criteria directly related to user satisfaction by analyzing existing international standards and certification systems (e.g., WELL, LEED, BREEAM, DGNB, ASHRAE 55). Based on this, a new group standard-based evaluation method was developed, dualized into a ‘Pre-design User Satisfaction Index (D-USI)’ for the design phase and an ‘Operational User Satisfaction Index (O-USI)’ for the operational phase. In particular, this dualized system is designed to provide flexibility similar to existing building certification systems; when this evaluation method is adopted as an official certification system in the future, it allows building owners to obtain pre-certification at the design stage and, if desired, secure additional incentives through post-certification after completion. Finally, the applicability of this evaluation method was reviewed by simulating the developed method on a virtual smart public complex building, analyzing the differences between pre- and post-evaluations, and deriving facility improvement plans.

https://doi.org/10.5207/JIEIE.2026.40.5.334

Ji-Young Seo ; An-Seop Choi

An operating-condition search was developed to identify drone-mounted lighting conditions satisfying target-area minimum illuminance while accounting for photometric distribution. Using manufacturer-provided IES photometric data, illuminance was calculated for candidate heights and optical-axis orientations, and the required relative light output was determined.

https://doi.org/10.5207/JIEIE.2026.40.5.346

Min-Seo Kim ; An-Seop Choi

This study implements a text-tracking lighting system that recognizes the position of text using PaddleOCR, a lightweight deep-learning OCR model, and converts it into control values for a DMX512 luminaire. The system calculates the pixel deviation between the center of the camera image and the centroid of the detected text bounding box, and maps this deviation to the tilt angle of the luminaire. The relationship between pixel deviation and tilt value was first derived through direct measurement in a fixed configuration with a camera-to-text distance of 1,200mm. This distance was determined by considering that text falls outside the camera’s field of view below 500mm, while text recognition becomes unreliable beyond 1,200mm. The system was subsequently mounted on an autonomous mobile robot, in which the robot detects text through rotational scanning and aligns both the horizontal direction and the target distance based on proportional control, while the tilt of the luminaire governs the vertical direction, thereby extending the system into a two-axis coordinated control scheme. As a result, it was confirmed that the luminaire illuminates the detected text. This study removes the positional constraints of fixed luminaires and demonstrates the feasibility of a lighting infrastructure that responds actively to the position of a target object.

https://doi.org/10.5207/JIEIE.2026.40.5.353

Younjoo Cho ; An-Seop Choi

This study analyzed the effects of linear luminaire?workstation layout and partition presence on visual and non-visual lighting performance in offices using Relux. Four cases combining parallel or perpendicular workstation orientations with or without partitions were compared using workplane horizontal illuminance (Eh), eye-level vertical illuminance (Ev), melanopic equivalent daylight illuminance (M-EDI), and unified glare rating (UGR) under rated luminous flux and mean Eh normalized to approximately 500lx. Under rated conditions, the perpendicular layout showed higher Ev and M-EDI and lower UGR than the parallel layout at similar Eh levels, with M-EDI 250lx achieved at all seats without partitions and most seats with partitions. After normalization, these differences remained, but M-EDI was below 250lx in all seats. Even at 6,500 K with a relatively high melanopic daylight efficacy ratio (MDER) of 1.05, the recommended M-EDI level was not achieved, indicating that spectral characteristics alone are insufficient and luminaire?workstation arrangement should also be considered in office lighting design.

https://doi.org/10.5207/JIEIE.2026.40.5.360

Kyu-Hun Park ; Hee-Jin Kim ; Seung-Ryul Lee ; Woo-Young Shin ; Sun-Ho Yu ; Dong-Wook Kim

The increasing penetration of inverter-based resources (IBRs) and the expansion of HVDC/MTDC and DC grids have made conventional phasor-domain transient (PDT) simulations insufficient for assessing system dynamics, since weak-grid conditions, protection?control interactions, limiter operation, and DC-side transients require electromagnetic transient (EMT) analysis. EMT model submission and validation have therefore become critical for grid interconnection, planning, and operation studies. This paper reviews international standards, system operator guidelines, industry reports, and related literature on EMT model submission and validation for IBRs and HVDC/DC grids, and organizes the common requirements into five perspectives: submission, verification, acceptance, change management, and interoperability.

https://doi.org/10.5207/JIEIE.2026.40.5.372

An-Yeol Ko ; Do-Yun Kim

This paper proposes a field current and adaptive DC-link voltage control strategy to improve the regenerative braking performance of a Wound-Field Synchronous Motor (WFSM) drive system for electric vehicles. During regenerative braking operation, increasing the field current enhances the air-gap flux, resulting in improved regenerative torque and energy recovery. However, the increased field flux also raises the back electromotive force (EMF), which may cause current distortion and torque ripple under a fixed DC-link voltage condition.

https://doi.org/10.5207/JIEIE.2026.40.5.380

Jooran Yang ; Jinwoo Song ; Jin-Gyu Kim ; Hyungpyo Kim

This in vitro study evaluated the effects of externally applied electric-field conditions on multiwavelength optical signals and the feasibility of AI-based glucose concentration prediction. Aqueous glucose samples were measured using 650, 850, and 950nm light sources and a thermopile detector while varying the electrode configuration, excitation frequency, voltage, and waveform. Electric-field excitation increased the mean output from 0.905 to 1.155 V, corresponding to a 27.6% increase, and the four-electrode configuration produced an 18.8% higher mean output than the two-electrode configuration. The highest concentration linearity was obtained at 950 nm, 6 V and 240kHz (R² = 0.973). In group-wise cross-validation, the Random Forest model achieved the best predictive performance (R² = 0.808, MAE = 36.1mg/dL and RMSE = 62.9mg/dL). These results indicate that an external electric field may serve as an auxiliary stimulus that modulates optical signals by altering the dielectric and interfacial properties of the sample.

https://doi.org/10.5207/JIEIE.2026.40.5.390

Jaesang Kim ; Bonhyuk Ku ; Yechan Kim ; Inhoo Ban ; Giwon Go ; Jehui Lee ; Chanhyeok Jang ; Hyoungku Kang

This study compares the coil-level equivalent contact resistance and fast-discharge magnetic response of modified no-insulation (mNI) REBCO coils co-wound with STS 304 mesh 300 with those of a conventional no-insulation (NI) coil. Three mNI coils were fabricated under identical conditions to evaluate fabrication reproducibility, and critical-current and fast-discharge tests were carried out in liquid nitrogen at 77 K. The mNI coils showed critical currents of 98.0?114.5 A, comparable to 103.5 A for the NI coil. The coil-level equivalent contact resistance of the mNI coils was 1.650? 1.728mΩ, about 14 times higher than that of the NI coil (0.120mΩ), and the magnetic time constant decreased from 0.566 s for the NI coil to 0.038?0.040 s for the mNI coils, a reduction of approximately 14 times. The deviation in equivalent contact resistance among the three mNI coils was within 4.6% of the mean. These results confirm that co-winding with STS 304 mesh 300 increases the coil-level equivalent contact resistance and shortens the fast-discharge magnetic time constant without substantial degradation of the critical current.

https://doi.org/10.5207/JIEIE.2026.40.5.397

Joo-Hoon Park ; Joong-Ho Chang ; ; ; ; ;

The rapid growth of generative AI and large language models has increased power consumption and thermal loads in AI data centers, making efficient MEP (Mechanical, Electrical, and Plumbing) design increasingly important. This study analyzes how MEP design affects energy efficiency, reliability, total cost of ownership (TCO), and sustainability. Air, liquid, and hybrid cooling were evaluated with N, N+1, and 2N UPS redundancy architectures using PUE, WUE, CUE, availability, and expected downtime. For a hypothetical 10 MW facility with 100 racks, an average density of 100 kW per rack, and 8,760 h/year of operation, annual energy consumption, 10- and 15-year TCO, and UPS availability were quantitatively evaluated. Liquid cooling showed the lowest assumed PUE, while hybrid cooling offered a balanced trade-off between energy performance and infrastructure cost. The N+1 configuration substantially improved availability over N while requiring less redundant infrastructure than 2N. Based on these results, a four-layer integrated MEP design model is proposed: (1) rack-density-based zoned cooling, (2) matched UPS redundancy, (3) dedicated plumbing and Coolant Distribution Unit (CDU) capacity, and (4) an intelligent predictive-control layer for future operational optimization. The model integrates energy efficiency, reliability, economic feasibility, and sustainability, providing a quantitative basis for MEP configuration decisions in high-density AI data centers.