Earticle

The conventional chain conveyor system is driven by a single drive motor, so all processes are operated simultaneously and the process cycle is constrained by the slowest operation. Chain driving can also generate noise and wear dust and requires lubrication. This study is one of four related studies derived from the same flexible-drive-system development project. The four research areas are localization of the flexible drive system, development of the friction-bar drive system, reliability of the drive wheel, and prototype production and performance evaluation. This paper focuses specifically on prototype production and quantitative performance evaluation. A 20 m prototype line with eight drive units and two carriers loaded with 500 kg and 1,000 kg wasevaluated. A 720 h durability test was performed at 20 m/min. Position accuracy before and after the test and drive-wheel wear were evaluated. The measured post-test position deviations satisfied the criteria of 30 mm for the general control section and 5 mm for the precision control section. Average drive-wheel wear was 0.38 mm for the precision control section and 0.54 mm for the general control section. Because no same-condition comparative test with a chain conveyor or an imported FDS was performed, the conclusions are limited to the verified prototype test conditions.

The proliferation of intelligent swarm systems demands secure large-scale authentication. Abu Bakar et al.'s DPUAUT protocol integrates SmartNiC and PUFs but lacks thorough security validation. This study systematically reassesses DPUAUT, identifying three critical vulnerabilities: replay attacks via session ID reuse, identity forgery through PUF CRP reuse, and weak session-key derivation lacking forward secrecy. We propose a hardened redesign incorporating one-time nonce binding, PUF CRP renewal, and ECDH-based ephemeral key derivation. Evaluations across 10–500 nodes confirm the improved protocol effectively mitigates these vulnerabilities while preserving its lightweight authentication structure.

Advanced Air Mobility (AAM) requires an integrated control environment that can manage aircraft operation, battery status, weather conditions, and ground infrastructure information in a connected manner. This study proposes a data collection and integration architecture for AAM integrated control based on operation, battery, weather, and infrastructure data. The proposed architecture consists of data source, data collection, data integration, and decision-support layers, and includes object identification and time synchronization procedures to connect heterogeneous data generated from aircraft, battery management systems, vertiports, chargers, and weather information systems. To examine the applicability of the proposed structure, a condition-based simulation was conducted using arrival aircraft, low-state-of-charge aircraft, available chargers, available landing pads, and weather risk as representative operating conditions. The results show that the risk level increases when aircraft arrival demand and low-state-of-charge aircraft increase while charger and landing pad availability decreases. These results indicate that the proposed architecture can support stepwise risk level classification by integrating operation, battery, infrastructure, and weather conditions. Future research should quantify risk classification criteria by considering actual AAM demand, vertiport capacity, charging time, battery state variation, and weather conditions.

In modern manufacturing, transitioning from manual to autonomous control in CNC machining processes is crucial for improving productivity and product quality. While data-driven artificial intelligence (AI) technologies have been introduced, conventional black-box deep learning models often fail to reflect physical machining constraints, causing reliability issues on actual shop floors. This study proposes an autonomous control system for CNC machining processes integrating Asset Administration Shell (AAS)-based data standardization and an intelligent digital twin. To overcome the limitations of existing AI approaches, a physics-guided hybrid optimization model (integrating PINN-lite with 2-stage XGBoost) for deriving optimal cutting conditions and a vision AI-based predictive model for tool wear and remaining useful life (RUL) were developed. The proposed system was successfully deployed and verified in a real-world manufacturing environment. Performance evaluation certified by an authorized testing agency (KOTCA) demonstrated a 97.85% accuracy in optimal condition derivation and a 100% accuracy in tool wear prediction. The proposed closed-loop framework provides a highly reliable and practical solution for realizing level-3 autonomous factories in multi-variety, small-batch production environments.

This study analyzed the structure of online discourse that emerged during the planning and regulatory review of the Korean Air–Asiana Airlines merger. To this end, 316 YouTube comments posted between November 2020 and April 2024 were collected. After preprocessing, the data comprised 982 total keyword occurrences and 355 unique keywords. Keyword frequency and semantic network analyses based on document-level co-occurrence were conducted to identify major issues and structural relationships among key terms. Merger opposition, monopoly concerns, airfare increases, consumers, and airport slots were among the most frequently mentioned keywords. In the semantic network, merger opposition showed the highest Total Link Strength (TLS), while merger opposition and monopoly concerns both exhibited the highest degree. The strongest co-occurrence was observed between merger opposition and monopoly concerns, with other major connections involving airfare increases, consumers, and airport slots. These findings indicate that online discourse during the merger planning and regulatory review period involved interconnected discussions of market concentration, airfares, consumers, and aviation resource allocation. The observed relationships represent structural associations rather than causal relationships. As the data were limited to voluntarily posted YouTube comments, the findings cannot be generalized to the perceptions of airline consumers as a whole or to public opinion beyond the analyzed period. This study contributes to understanding online discourse surrounding airline mergers by empirically identifying major issues and their structural relationships during the merger planning and regulatory review process.

Patidar et al.'s blockchain-based protocol with zero-knowledge proofs offers privacy but lacks thorough security analysis. We identify three vulnerabilities: replay-prone proof binding, trusted-setup compromise, and absent forward secrecy. Our hardened redesign incorporates ephemeral Diffie-Hellman, deterministic nonce binding, and transparent setup. Evaluation on 10–500 nodes shows the improved protocol mitigates vulnerabilities while maintaining lightweight efficiency.

According to the Ministry of Employment and Labor, 338 people were injured in confined space suffocation accidents between 2014 and 2023, 136 of whom died. Accidents are especially concentrated in wastewater treatment facilities, septic tanks, and livestock manure treatment facilities, where harmful gases are heavier than air and accumulate at the bottom, causing suffocation and death. However, there is a lack of relevant research in Korea. This study analyzed the ventilation performance to keep the hydrogen sulfide concentration below the safety standard concentration. The number, location, and amount of ventilation were set as design variables under the condition of a floor oxygenator and an exhaust fan, and the conditions for a concentration below the permissible standard were derived. Concentration distributions under various scenarios were analyzed to suggest efficient ventilation design in confined spaces. The results can be utilized as a guide for ventilation design and worker safety.

This preliminary study examined wearable heart rate responses during the initial ten dual flights and the first solo flight in 30 student pilots enrolled in a private pilot course. Maximum and mean heart rates were continuously recorded using a Xiaomi Smart Band 9. Differences across the ten dual flights were analyzed using repeated-measures ANOVA with Greenhouse–Geisser correction, and paired-samples t-tests were conducted for stage comparisons. Significant session main effects were found across dual flights for both maximum heart rate, F(4.96, 143.69)=82.18, p<.001, partial 2=.739, and mean heart rate, F(3.04, 88.26) = 45.92, p<.001, partial 2=.613, showing progressive physiological adaptation. Both maximum and mean heart rates during the first dual flight were significantly higher than those during the first solo flight (t=6.09, p<.001 and t=4.57, p<.001, respectively). Notably, heart rates rebounded significantly from the tenth dual flight to the first solo flight, suggesting a resurgence of physiological arousal associated with flying without an instructor. These findings provide empirical baseline data on pilot workload across training milestones. Future research should integrate objective flight-phase segmentation, subjective mental workload scales, and reference ECG instrumentation.

Advanced Air Mobility (AAM) integrated control requires a reliable data management structure that can preserve the integrity and traceability of operational records generated from aircraft, batteries, vertiports, and control systems. This study proposes a blockchain-based management architecture for verifying the integrity of AAM operational data. The proposed architecture separates original data and verification information by storing high-frequency state data in off-chain storage while registering Record IDs, hash values, timestamps, and transaction information on-chain through registration, linkage, verification, and change-history procedures. To evaluate the storage characteristics of the proposed structure, cumulative on-chain data volumes were compared between full on-chain and selective on-chain management methods according to operating time and the number of aircraft. The results show that the selective on-chain method reduced the on-chain data volume by approximately 99.986% under the defined analysis conditions. This indicates that selectively registering records requiring traceability and integrity verification can reduce blockchain storage burden while maintaining verification capability. Future research should consider actual transaction structures, digital signatures, metadata overhead, batch registration, and operational data generated from real AAM environments.

In this study, we observed the occurrence of liquid crystal (LC) alignment when unpolarized ultraviolet (UV) light was irradiated onto polyimide (PI) surfaces used as alignment layers. Although numerous studies have previously reported that the oblique irradiation of unpolarized UV light induces optical anisotropy on PI surfaces, the specific alignment mechanism has not been sufficiently elucidated. Generally, it has been understood that the maximum difference between the inherent P-wave and S-wave polarization components occurs when unpolarized UV light is incident at an angle of 45°, a finding that our research group has also previously published. However, practical experimental results have shown that the most superior LC alignment is achieved at an incident angle of approximately 60°, presenting a challenge for theoretical interpretation. In this paper, we successfully demonstrated the LC alignment mechanism using unpolarized UV light by establishing a correlation between theoretical simulations and experimental data, specifically explaining why an incident angle of 60° produces the most favorable alignment in the final LC cell.

This study proposes a 3600 rotating universal intelligent add-on platform combining YOLOv8 vision perception and a profile-shifted circular rack-and-pinion mechanism to overcome the angular limits of conventional rotating appliances. Implemented on a Raspberry Pi 5, the system calculates real-time target position errors while suppressing motor hunting via an EMA filter and a deadzone control (±26 pixels). To prevent gear undercut during FDM 3D printing and avoid mechanical locking due to material thermal shrinkage, a profile shift coefficient (x=0.36) and a 0.50 mm effective composite tolerance were applied. Dynamic step response testing under an 80-pixel input condition demonstrated a fast settling time of 0.85 seconds without overshoot. Under standard indoor conditions (above 500 lx, within a 3 m radius), the platform achieved a target detection accuracy exceeding 95% with an average processing speed of over 21.5 FPS. Furthermore, a 60-minute continuous operation test verified that key component temperatures saturated stably (CPU maximum 46.6°C), demonstrating mechanical and thermal durability without structural gear deformation or thermal throttling.

Single-pilot certification has generally been understood as a function of aircraft weight or type-certification category. This study analyzes the FAA's airworthiness standards for determining minimum flight crew and compares the certification histories of 21 derivative models across four type certificates (A22CE, A27CE, A1WI, A00014WI) in the Cessna Citation family. The Model 550 (type-certified 1978, 6,033 kg) required two pilots under the transport category, whereas the heavier Model 525B (2004, 6,291 kg) was approved for single-pilot operation under the commuter class. Physical characteristics alone do not account for this reversal; the analysis suggests that the regulatory status at the time of application influenced which certification track each model could enter. The trajectory runs from the creation of the commuter category in 1987, through individual exemptions and special conditions for turbofan airplanes, to codification in 2011. One type rating designation may encompass both single-pilot and two-pilot certificated models, producing two structurally distinct routes to single-pilot operation; the exemption route is being terminated by FAA policy in 2026. Part 25 retains the prescriptive criteria of Appendix D established in 1965, whereas Part 23 shifted to performance-based standards in 2016. Implications for domestic light aircraft and Advanced Air Mobility certification are discussed.

This study examines how airline selection attributes influence reuse intention through the mediating roles of customer satisfaction and trust. Five attributes—safety, pricing, in-flight service, flight operation service, and brand image—were modeled as antecedents of satisfaction, trust, and reuse intention. A survey of 503 airline passengers was analyzed with SPSS 27.0 and AMOS 27.0 using structural equation modeling and a bootstrap mediation test. Pricing, in-flight service, and brand image significantly increased satisfaction, whereas safety, flight operation service, and brand image increased trust and pricing decreased it. For reuse intention, flight operation service had a positive and pricing a negative direct effect. Satisfaction and trust both strongly predicted reuse intention, and satisfaction also enhanced trust. Mediation analysis showed that in-flight service and brand image affected reuse intention only indirectly, through satisfaction and trust (full mediation), whereas flight operation service had a significant direct effect but no significant indirect effect. The findings clarify the satisfaction- and trust-based pathways through which airline selection attributes lead to reuse intention.

This study presents a comparative thermal-fluid analysis of Wireless Power Transfer(WPT) receivers of 50kW for electric vehicle and 1.5kW for AMR/Robot. Conjugate heat transfer simulations were performed to investigate temperature, flow characteristics, and heat transfer characteristics of two WPT receiver systems with different power levels, system configurations and application environments. For the 50kW receiver, the coolant temperature increased 1.77℃, while the coolant pressure loss was 17.587kPa. The heat absorbed by coolant was approximately 2.21kW, corresponding to about 97.5% of the total heat generation. For the 1.5kW receiver, natural convection circulation was formed through housing openings. The IMN inductor showed the highest temperature of 154.40℃ below its Curie temperature 220℃. System level experiments were also conducted for the 1.5kW WPT system to examine its thermal behavior under operating conditions. In addition, 1.5kW WPT system installed on an actual AGV, which operated normally during driving and wireless charging without overheating or charging interruption. The results demonstrated that thermal management design for WPT receivers with different power levels and application environments should comprehensively consider the cooling method, heat source distribution, heat transfer paths, flow uniformity and pressure loss.

This study analyzed the dynamic thermal loss characteristics of the high-voltage battery in a series-parallel hybrid vehicle based on the FTP-75 driving cycle. A series-parallel hybrid powertrain model was constructed using MATLAB/Simulink R2025b, and the conditions of a 1,575 kg vehicle weight, a NiMH high-voltage battery(201.6[V], 6.5[Ah]), and an initial SOC of 60[%] were applied. The battery's thermal loss was calculated based on the electrical loss resulting from the charge/discharge current and internal resistance. The simulation results showed that the thermal loss of the high-voltage battery varied significantly over time during the acceleration, deceleration, and regenerative braking phases of the FTP-75 cycle, with a maximum instantaneous thermal loss of approximately 0.15–0.18[kW]. In contrast, during extended idle(stop) periods, the battery's thermal loss decreased to a level near zero. These results demonstrate that the thermal load of a hybrid vehicle's battery is closely related not only to the average energy consumption but also to the instantaneous current fluctuations that occur under actual driving conditions.

In this study, a non-migration 3-layer PE-based sealing film was developed to prevent performance degradation and electrostatic metal impurity adsorption in secondary battery cathode materials. To overcome the limitations of conventional Japanese CPP films, a 3-layer co-extrusion structure was designed. The Skin-1 layer with MAH-g-PE achieved a peel strength of 8.5 N/25mm with the aluminum barrier layer. The Core layer employed low-MI PE, providing high stability with a tensile strength of 22.8 MPa and the Vicat softening point of 132℃. The Skin-2 layer, contacting the cathode material, incorporated metallocene PE to achieve low-temperature sealability(sealing strength of 40.5 N/25mm) and a low friction coefficient(0.88) without slip agents. Surface-modified CNTs were chemically anchored to control surface resistivity at 5.73×1012Ω/sq and reduce metallic impurity adsorption by up to 55.6%. High property retention over 95% after 500-hour environmental tests demonstrated long-term reliability, contributing to supply chain stabilization.

This study analyzes the rotorcraft fleet structure in Korea and the maintenance scope of domestic Approved Maintenance Organizations (AMOs). The analysis covered 238 registered rotorcraft representing 54 detailed aircraft types. Of these, 42 types (77.8%) had five or fewer registered aircraft, indicating a diversified and fragmented demand structure. The ratings and detailed limitations of domestic AMOs were analyzed by aircraft type and maintenance area, including line maintenance, base maintenance, engine, and major component maintenance. The results show that approved scopes for line maintenance and certain base maintenance tasks are available for major rotorcraft types, whereas approved scopes for engine and major component maintenance are more selectively available and subject to specific limitations. Based on these findings, this study proposes selective specialization in strategic aircraft types and critical maintenance areas rather than uniform localization across all rotorcraft types.

This paper is a study on the optimal design of a 3,100 mm diameter baffle plate installed in large-diameter piping of large-scale plants using finite element (FE) analysis. Since classical plate theory requires a thickness of 163 mm for an unreinforced plate, which is unrealistic, a grid-type stiffener was adopted. After verifying that the maximum stress error was within 2.35% by comparing the shell element analysis model with the theoretical solution, a parametric analysis was performed on eight design options (BP1–BP8) and four boundary condition models (conditions A–D) under a design pressure of 15 bar and combined hydrostatic load. As a result of the evaluation based on the effective deformation criterion (1.8275 mm), the original design option (BP1) was found to be unsuitable, and BP8 with a baffle plate thickness of 50 mm, a stiffener thickness of 40 mm, and the height of 360 mm, was derived as the optimal option satisfying the criterion.

In this study, we propose and analyze data augmentation techniques tailored for injection-molded product surface defect detection using deep learning–based vision inspection systems. To alleviate the scarcity and imbalance of defect samples in real production lines, a data augmentation strategy consisting of four categories—geometric transformation, photometric transformation, defect-aware local augmentation, and synthetic defect generation—is designed. The effectiveness of the proposed strategy is evaluated using a ResNet-50–based classification model and a YOLOv8-S–based defect detection model, trained on real images acquired from an industrial injection molding process. Experimental results show that, compared to the baseline model trained without augmentation, the proposed strategy improves the F1-score of defect classes by approximately 10–15 percentage points and enhances mAP@0.5 by about 8–12 percentage points. In particular, the recall of rare defect types such as micro-cracks and weld lines is significantly improved, indicating that data augmentation plays a crucial role in increasing the practicality of automatic inspection in injection molding processes. The findings of this work provide useful guidelines for implementing deep learning–based visual inspection systems in real industrial environments with limited defect data.

This study evaluated the thermo-structural integrity and environmentally assisted fatigue (EAF) behavior of an i-SMR CRDM housing under daily load-following transients (100%→50%→100% power) based on ASME Section III NB-3200. Sequentially coupled 2D FEA on a 3 mm STS316L housing showed a maximum von-Mises stress of 232.79 MPa at 100% power and 217.68 MPa at 50% power, yielding a cyclic stress range of 15.11 MPa. For a 60-year design life (200cycles), the air fatigue damage (Dair) was with a minimum safety factor of 3.384. Applying an NUREG/CR-6909 Fen factor of 6.03 resulted in a cumulative usage factor (CUFen) of , well below the 1.0 limit. These results confirm that the thermal stress induced by load-following transients is significantly mitigated by the thin-walled design, ensuring structural robustness and substantial safety margins over the 60-year design life.

Fatigue life prediction of an autofrettaged thick-walled pressure vessel subjected to a pulsating high internal pressure was made to prevent catastrophic failure of the pressure vessel. Elastic-plastic stress analysis of the autofrettaged pressure vessel was performed by using finite element method, and low-cycle fatigue test was performed to determine fatigue properties of the pressure vessel steel. Fatigue life of the pressure vessel was predicted using the finite element stresses and fatigue damage parameter, resulting in 24,521 cycles. Simulation fatigue test in the laboratory was performed in order to verify the predicted fatigue life of the pressure vessel using the C-type simulation test specimen. Predicted fatigue life and simulated fatigue life were in good agreement.

This study analyzed 40 helicopter accidents and serious incidents that occurred in Korea from 2005 to 2022, based on final investigation reports published by the Aviation and Railway Accident Investigation Board. Mission type, flight phase, and accident type were classified into five, four, and four categories, respectively. Because of the small sample size and sparse contingency tables, r×c Fisher’s exact tests and Cramér’s V were applied. Significant associations were found between mission type and flight phase (p=0.009), mission type and accident type (p=0.029), and flight phase and accident type (p=0.016), with Cramér’s V ranging from 0.425 to 0.432. Aerial-application accidents were concentrated in low-level mission phases and mainly involved collision or external-work-related events, while water-impact accidents occurred during water-approach operations. The results suggest that helicopter safety management and training should consider mission type and flight phase together.

In this study, static thermo-structural integrity and environmentally assisted fatigue (EAF) behavior were evaluated according to housing thickness reduction (10 mm to 3 mm) for an i-SMR CRDM housing. Finite element analysis was conducted on the STS316L housing under operating conditions (325 °C, 15.5 MPa) and 200 transient cycles based on ASME Section III NB-3200. To account for the primary water coolant environment, an environmental fatigue correction factor (Fen = 6.03) derived from NUREG/CR-6909 Rev. 1 was applied. The air fatigue damage (Uair) remained at a negligible across all thickness conditions, confirming significant over-design in the baseline 10 mm model. Although the actual safety factor decreased from 33.60 (10 mm) to 12.21 (3 mm), the 3 mm design maintained a substantial safety margin well above 1.0. Considering environmental effects, the cumulative usage factor (CUFen) for the 3 mm design was , far below the ASME allowable limit of 1.0. Consequently, reducing the housing thickness to 3 mm ensures structural robustness and 60-year operational integrity.

This study proposes a multi-stage signal stabilization structure for RGB-D camera-based robot arm teleoperation using hand-tracking information. Vision-based hand tracking with MediaPipe Hands provides a contactless input method for multi-degree-of-freedom robot control, but directly applying raw tracking results to robot commands can cause unintended command changes and unstable motion. To address this, stabilization processes are applied at three stages of the control pipeline: vision-based hand control input, robot target command and trajectory, and joint command continuity. The proposed structure was evaluated on a robot arm teleoperation system through Hold Jitter and Pick-and-Place experiments under Filter-OFF and Filter-ON conditions. In the Hold-Jitter experiment, XYZ command jitter decreased from 1.675 mm to approximately 0 mm, while Roll/Pitch command jitter was reduced by 56.2%. In the Pick-and-Place task, the first-attempt success rate increased from 33.3% to 63.3%, and the mean task completion time was reduced by 37.9%. These results, based on three participants, indicate reduced command fluctuations and a positive trend toward improved teleoperation performance.

Sloshing in partially filled vehicle water tanks can induce large free-surface oscillations and dynamic loads following changes in vehicle motion. In this study, corrugated walls were applied to reduce sloshing without additional internal baffles. The amplitude A, number of waves N, and relative phase were varied, and 82 configurations were analyzed through two-dimensional transient Volume-of-Fluid (VOF) simulations using ANSYS Fluent. A 50% filling condition with acceleration from 0 to 6 s followed by constant-speed motion was considered. Sloshing performance was evaluated using the RMS and mean amplitude of the free-surface displacement. The results showed that the effect of the corrugated wall depended strongly on A, N, and phase arrangement, and some configurations showed poorer performance than the flat-wall tank. Among the tested cases, Out-Phase Case 41 exhibited the best overall free-surface behavior, with an RMS reduction of approximately 26.46%. These results indicate that corrugated-wall performance should be evaluated based on the geometric combination and phase arrangement rather than the presence of corrugation alone.

Welding is widely used in various industrial fields because of its simple joint configuration, high joint efficiency, and excellent airtightness. However, welded structures may be susceptible to corrosion depending on the service environment; therefore, understanding the corrosion characteristics of welded joints is important. In this study, STSY304 stainless steel was used as the base material, and gas tungsten arc welding (GTAW) was performed in the flat position using STSY-308 filler rods with a diameter of 2.4 mm and a length of 1,000 mm. The specimens were exposed to ambient air and groundwater conditions for 100, 500, 1,000, and 1,500 h, and changes in specimen weight and the corrosion behavior of the face and root beads were evaluated. Under ambient air conditions, little change in specimen weight was observed up to 1,500 h, and no distinct corrosion was observed on the face bead. However, slight corrosion was observed at the start and end regions of the root bead. Under groundwater conditions, corrosion on both the face and root beads became more evident with increasing exposure time. These results indicate that the corrosion behavior of GTAW-welded STSY304 stainless steel varies depending on the exposure environment, exposure time, and bead location. The results of this study may provide useful fundamental data for corrosion assessment and corrosion-prevention design of stainless-steel welded structures.

A four-seat tandem-wing electric vertical take-off and landing aircraft was conceptually designed, and a nominal quarter-scale prototype was fabricated and tested in hovering flight. The design payload and target mission range were 340 kg and approximately 100 km, respectively. Eight lift rotors and one pusher propeller were arranged in a lift-and-cruise configuration. At a representative full-scale mass of 1,720 kg, a hover-to-maximum-thrust ratio of 0.65 required a total maximum static thrust of 25.96 kN. A preliminary maneuver envelope gave a positive stall speed of 117.5 km/h and a maneuvering speed of 229.1 km/h under the adopted assumptions. The subscale component mass budget was 18.125 kg. A separate 15.945 kg component configuration gave a longitudinal center of gravity of 979 mm aft of the nose; the two configurations were distinguished in the mass-property assessment. The fabricated prototype completed hovering flight in a GPS-assisted position-hold mode, and stable hovering was observed. The test confirmed initial hovering capability of the integrated prototype. Full-scale performance and quantitative flight-control accuracy were outside the evaluation presented here.

This study evaluates the thermal response and cooling performance of a liquid-cooled electric vehicle battery pack under varying volumetric heat generation rates. A three-dimensional cooling model was constructed based on an actual electric vehicle battery pack, and transient thermal-fluid simulations were performed using ANSYS Fluent. To isolate the effect of battery heat generation, the geometry, coolant conditions and boundary conditions were kept identical, while the volumetric heat generation rates were set to 17,000, 34,000 and 170,000 W/m³. Under these identical cooling conditions, the maximum battery module temperatures were 307.755 K, 322.129 K and 386.690 K, respectively. As the volumetric heat generation rate increased, the maximum temperature also increased, with a pronounced rise under the highest heat-generation condition. These results indicate that the thermal load directly affects the thermal response and cooling performance of the battery pack and that, under high thermal-load conditions, the existing cooling configuration may become insufficient to maintain a comparable battery temperature. The results provide fundamental data for evaluating thermal responses and improving battery thermal management system design under different heat-generation conditions.

Regional tourism demand is an important regional factor in aviation demand research, but different big-data indicators may capture tourism activity in different ways. This study examines three behavior-based indicators generated from different data systems: navigation destination searches, reflecting interest in visiting a region; mobile-based non-resident visits, reflecting actual regional visits; and estimated credit-card-based tourism consumption, reflecting tourism-related economic activity. Although these indicators have been used in previous studies, few studies have directly compared their relationships across the same regions over the same period. Using data from 229 local areas in Korea from 2023 to 2025, this study employed correlation, partial correlation, regression, and supplementary spatial analysis. The results showed strong relationships among the three indicators, although these relationships weakened after controlling for regional size but remained statistically significant. These findings suggest that the three indicators are closely related while reflecting different aspects of regional tourism activity, highlighting the importance of considering their measurement characteristics when selecting and interpreting tourism-demand indicators. Academically, this study contributes to clarifying how regional tourism demand can be measured and interpreted using big-data indicators generated from different data systems. Practically, the findings highlight the need to consider indicator characteristics when using regional tourism data for tourism and aviation-related analysis. In particular, the study provides a preliminary empirical basis for selecting and interpreting regional tourism-demand indicators in future research linking regional tourism activity with airport passenger demand and operations.

This study addresses the system design and prototype fabrication of a non-contact safety module for swing automatic doors using a Time-of-Flight (ToF) sensor. Conventional IR safety beams, overhead sensors, and door-mounted sensors have limitations in continuously monitoring the changing swing radius, rear-side region, and pinch zones. The proposed module integrates a ToF sensor, MCU, power and I/O interfaces, PCB, control software, and a mechanical enclosure. The development procedure covers sensor characterization, safety operating conditions, circuit and PCB implementation, mechanical integration, Lab Test, and accredited EMC testing. By combining real-time distance information with the door operating state, the system provides a basis for distance-based obstacle detection and safe opening or stopping control. The present findings establish the feasibility of prototype integration and continuous distance-output acquisition under the reported laboratory conditions; they do not establish obstacle detection rates, door stopping success rates, or collision prevention performance during actual door operation.