본 연구에서는 해양플랜트 및 산업용 덕트에서 발생하는 유동 기인 소음을 저감하기 위해 다중공진구조 기반 광대역 소음기를 설계하고, 그 성능을 실험 및 수치해석으로 검증하였다. 제안된 소음기는 공진 특성이 다른 레이어를 주기적으로 배열해 1–3 kHz 구간에 서 국소 공진 차단대역과 Bragg 산란 밴드갭이 동시에 나타나도록 설계되었다. 음향해석 결과, 무유동 조건에서 약 50–60 dB의 삽입손실 이 확보되었으며, 유속 3 m/s와 9 m/s 조건에서도 10–25 dB의 감쇠 성능이 유지되었다. 실험과 수치해석은 전체 주파수 범위에서 정성적 으로 일치했으며, 고속 유동에서의 성능 저하는 공진기 목 주변의 난류 교란과 재생소음(regenerated noise) 영향으로 나타났다. 또한 Bragg 기반 밴드갭은 유동환경에서도 비교적 안정적으로 유지되어 구조적 차단 메커니즘이 성능 저하를 방지하는 데 기여함을 확인하였다. 본 연구는 흡음재 없이도 구조적 설계만으로 광대역 소음 제어가 가능함을 입증했으며, 향후 해양플랜트 및 산업용 덕트 설계 기준 마련에 기여할 수 있다.

AlGaN/GaN high-electron-mobility transistors (HEMTs) are widely employed in power electronics and high-frequency systems because of their high-speed switching and high-power capabilities. However, conventional structures suffer from issues including mobility degradation and device deterioration at elevated temperatures, as well as current collapse and increased gate leakage under high-voltage operation. To address these issues, this work proposes metal-oxidesemiconductor HEMTs (MOS-HEMTs) incorporating an Al2O3/HfO2 stacked gate dielectric. Al2O3 provides excellent chemical stability at the AlGaN interface, reducing interface trap density, while its wide bandgap suppresses electron tunneling and lowers gate leakage. In contrast, HfO2 offers a high dielectric constant, improving oxide capacitance and enhancing charge control even at the same physical thickness. The stacked Al2O3/HfO2 structure leverages the complementary advantages of both materials, enabling threshold voltage stabilization and effective suppression of leakage current. This design mitigates the thermal and electrical reliability concerns of conventional HEMTs and paves the way for high-performance GaN-based devices suited to next-generation high-speed, high-power applications such as artificial intelligence, 5G communication, and LiDAR systems.

This study examined the relationships between acoustic activity of the finless porpoise (Neophocaena asiaeorientalis) and marine environmental variables in Hadong, in the southern coast of Korea, using long-term passive acoustic monitoring. Acoustic data were collected with a hydrophone (F-POD) from July 8 to August 16 2023, and acoustic indices (DPM, DP10M, and click-based metrics) were integrated with in situ observations and model analysis environmental data. Generalized additive models indicated that chlorophyll-a and dissolved oxygen were the main predictors of acoustic activity whereas physical oceanographic variables (temperature, salinity, and sea surface height) had no significant effects. Chlorophyll-a showed a strong non-linear positive effect with finless porpoise activity increasing rapidly up to approximately 2 mg/m³ and then reaching a plateau. Dissolved oxygen exhibited a negative linear relationship, implying indirect ecological effects mediated by prey availability. In addition, current velocity was negatively related to click intensity. These results indicate that finless porpoise habitat use is more closely associated with productivity-related factors than with physical conditions. This research offers quantitative insights into prey-driven habitat selection, supporting the development of management and bycatch mitigation strategies.

This study investigates the thermo-mechanical behavior and residual stress characteristics of friction stir welding (FSW) in an aluminum inverter housing using finite element analysis (FEA). FSW experiments were first conducted under various tool rotation and traverse speed conditions, and temperature histories were measured using K-type thermocouples. The optimal process condition was identified through tensile testing, and the heat input was estimated by comparing experimental and numerical results. The estimated heat source was incorporated into a transient thermal elasto-plastic analysis to evaluate deformation and residual stresses in an inverter housing model. The results indicated that residual stress distributions varied depending on the welding start position. In particular, when welding started at P3 (near thick ribs and bosses) residual stresses were reduced by approximately 30% compared to P1, owing to the higher local stiffness and enhanced heat dissipation that mitigated temperature gradients. Conversely, welding initiated at P1, a flat region with insufficient reinforcement, resulted in higher stress concentrations. These findings confirm that the welding start position significantly influences residual stress behavior in inverter housings and provide fundamental insights for developing residual stress control strategies in FSW of large-scale components.

본 연구는 강원특별자치도 홍천군 일대를 대상으로 멸종위기야생생물 Ⅰ급인 산양(Naemorhedus caudatus)의 서식 지 적합성(Habitat Suitability Index, HSI)을 정량적으로 평가하고, 카메라트래핑(Camera Trapping)을 통해 모형의 예측력을 검증하였다. 서식 변수는 고도, 경사, 사면향, 절벽·암괴지대, 수계 거리, 식생 유형, 도로 거리, 인위적 간섭 거리 등 8개로 선정하였으며, 각 변수의 적합도지수(Suitability Index, SI)는 선행연구와 현장 생태지식을 반영하여 0–1로 표준화하였다. 입력자료는 30 m 해상도로 전처리한 뒤 100 × 100 m 평가격자(총 1,200개)로 집계하여 ArcGIS 10.8을 이용한 공간분석을 수행하였다. 분석 결과, 연구지역의 매우 적합(Most Suitable) 구간은 27.4 %, 적합(Suitable) 구간은 43.3 %로, 전체의 약 70.7 %가 산양 서식에 적합한 지역으로 평가되었다. 그러나 절벽·암괴지대 등 피복자원이 불균등하게 분포하여 서식지는 일부 핵심 패치(Core Habitat)에 집중되는 경향을 보였다. 무인센서카메라 검증 결과, 전체 53개 설치 지점 중 22개(41.5 %)에서 산양이 확인되었으며, 출현의 88 %가 HSI상 적합 이상 구간에서 기록되어 모델의 예측력이 실제 분포와 높은 일치도를 보였다. 계절별 출현은 봄·여름·가을(3–11월)에 집중되어, 본 지역이 인근 개체군 간 이동 회랑 기능을 수행할 가능성을 시사하였다. 보전 측면에서 절벽·급경사 계곡 등 커버자원이 집중된 지역은 핵심 서식지로서 우선 보호가 필요하며, 침엽수 우점림은 혼효림 전환과 하층식생 복원을 통해 먹이자원을 확충해야 한다. 또한 도로 및 건축물 주변에는 300–600 m 완충구역 확보와 생태통로 조성이 요구된다. 결론적으로 본 연구의 HSI 모형은 산양 서식지의 공간적 질과 분포를 정량적으로 설명하고 현장자료로 검증함으로써, 향후 서식지 복원·생태축 연결 및 데이터 기반의 종 보전정책 수립에 활용될 수 있는 과학적 근거를 제시하였다.

본 연구는 장대형 터널 입구에서 발생한 TNT 폭발로 인해 터널 내부로 전달되는 충격파 하중의 거리별 분포를 수치적으로 분석하 였다. 특히 마하파가 평면파로 전이되는 구간에서 최대 압력 및 충격량의 감쇠 특성을 정량적으로 규명하는 데 중점을 두었다. 해석에 는 고폭발물 해석에 특화된 도구인 ANSYS AUTODYN 2023R1을 사용하였으며, 25제곱미터 정사각 단면을 가진 직선형 터널을 대 상으로 TNT 중량 10kg, 50kg, 100kg, 500kg 조건을 적용하였다. 터널 중심선 상의 관측 지점을 통해 데이터를 수집하고, 거리(D)를 폭 약 중량(W)으로 나눈 환산 거리(Z = D/W)를 도입하여 중량 간 비교를 수행하였다. 분석 결과, TNT 중량에 따라 절대 응답 값은 달랐 으나 정규화된 축에서는 최대 압력과 충격량이 유사한 감쇠 경향을 나타냈다. 이러한 결과는 터널 입구부 폭발 시 발생하는 하중 분포 가 환산 거리 기준으로 일정한 패턴을 갖는다는 점을 보여주었으며, 향후 방호 설계, 위험 구역 산정 및 폭발 피해 예측 등에 활용 가능 한 기초자료를 제공할 수 있을 것으로 기대된다.

The growing global demand for Agaricus bisporus has focused on automated harvesting systems, prompting the adoption of artificial intelligence to enhance precision and efficiency. This study aimed to prove the possibility of automated analysis for mushroom phenotypic traits including pileus diameter and color parameters (L*, a*, b*) by using AI model, YOLOv11-seg. Mushroom images were obtained in custom-designed imaging chamber and image training was processed using YOLOv11-seg. By achieving an mAP50 of 0.96, model demonstrated high detection and segmentation performance with stable predictive behavior. To evaluate biological validity, predicted phenotypic traits were compared with mechanically measured values. Pearson correlation coefficient analysis showed that the correlation coefficient for chromaticity was above 0.69, while the correlation coefficient for shoulder diameter was very low at 0.03. Linear regression analysis showed correlations above 0.69 for all phenotypic traits, indicating that the model analysis reflected the actual measurement variation well. Mean absolute error (MAE) analysis showed less than 10% error of 1.32, 2.43, 0.55, and 0.90 in pileus diameter, L*, a*, and b*, respectively, resulting in significant model accuracy. Based on these results, YOLO-based estimation of pileus area was processed to prove the model’s capacity to extract phenotypic traits beyond the limits of traditional analysis. These results indicate that AI models including YOLOv11 show the possibility of the automated growth monitoring for the next-generation smart cultivation systems.

Tricholoma matsutake, one of the most favorable ectomycorrhizal mushrooms, forms a symbiotic relationship with its host, Pinus densiflora. In this study, co-cultivation of T. matsutake mycelium with bacteria from fairy rings was conducted to explore artificial cultivation. Among the isolates tested, strain B22_9_B28 promoted mycelial growth across five T. matsutake isolates: KMCC05631 from Yangyang-gun (124.23%), KMCC05632 and KMCC05633 from Yeongdeok-gun (127.68% and 156.61%, respectively), and KMCC05634 from Yeongdong-gun (153.31%), and KMCC05644 from Bonghwa-gun (171.59%). 16S rRNA sequence analysis suggested that B22_9_B28 may represent a novel species of Paenibacillus. These results highlight the potential of a new Paenibacillus species with pan-regional growth-promoting effects on T. matsutake mycelium, offering a promising avenue for the artificial cultivation of this valuable mushroom.

In this study, the development of a new white beech mushroom (Hypsizygus marmoreus) cultivar, ‘Baekmaru24’, is described, and its growth characteristics and field adaptability are evaluated. ‘Baekmaru24’ was bred from the parent strains, KMCC05528 and KMCC05529, through controlled crossing and multi-stage line selection, resulting in the final elite line, ‘HWD-22-116’. Mycelial growth tests demonstrated that the cultivar had superior growth under low temperatures (10–15 °C) and on YM medium, with optimal growth at 20–25 °C. In indoor bottle cultivation, the per-bottle yield was 146 g per 850 mL, which was 8% higher than that of the control cultivar (135 g). The fruiting bodies had stipes with a mean of 70.5 mm, which is approximately 10 mm longer than that of the control, and they had highly uniform clusters, enhancing marketability. Field trials at two farms confirmed a significant increase in yield of approximately 11 % over existing commercial cultivars, together with a generally superior morphology, including larger caps, longer stipes, and greater tissue firmness. Somatic incompatibility testing revealed a distinct demarcation zone between ‘Baekmaru24’ and its parent strains, indicating that it is a genetically independent cultivar. Overall, these results demonstrate that ‘Baekmaru24’ has stable growth, high productivity, and favorable fruiting-body characteristics under both controlled and farm conditions, supporting its potential as a high-quality commercial mushroom cultivar.

The engineered materials arresting system (EMAS) is a safety facility installed at the end of runways to safely stop aircraft when runway overruns occur. The EMAS comprises porous panels composed of specialized materials; however, direct exposure to environmental factors, such as moisture infiltration, freeze–thaw cycles, and ultraviolet radiation, may cause performance degradation. In regions with four distinct seasons and significant temperature variations, such as South Korea, changes in the physical properties and durability of porous panels can pose significant challenges. Therefore, a protective top coating must be applied to EMAS panels to protect the panels from environmental stress and ensure long-term durability. This study presents a preliminary investigation into the development of a high-performance polyureabased top coating to effectively protect the components of an EMAS and crushable concrete panels as well as to maintain the system’s long-term durability and arresting performance. First, optimal formulations were determined via a design study, where the index ratio (the equivalent ratio of polyurea resin to the curing agent) and the NCO content of the isocyanate component were varied. Second, the curing behavior, mechanical properties, and temperature dependence were evaluated. Polyurea—a high-performance elastomer formed by the reaction between isocyanate and amine-based curing agents—exhibits rapid reactivity, complete waterproofing, excellent flexibility, and elasticity, thus satisfying the essential requirements of EMAS top coatings. Considering the balance between stiffness and flexibility, an index ratio of 1.05 and an NCO content of 16.0% were identified as the optimal mix design. Mechanical testing demonstrated a high tensile strength of 20.0 MPa, an outstanding elongation at break of 388%, and a tear strength of 100 N/mm, thus indicating sufficient durability and flexibility to withstand aircraft jet blast and temperature fluctuations. Temperature-dependence tests confirmed that the elongation remained at 136% (at -20 °C) and the tensile-strength ratio at 68% (at 60 °C), thus demonstrating that the coating can maintain stable performance in environments with significant seasonal temperature variations.

본 연구의 목적은 국내 여성 중간관리자를 대상으로 일-삶 균형과 관계지향 리더십의 관계에서 주요한 전제가 되는 조직공정성과 그 사이에서 조절 영향을 주는 CEO의 성평등인식에 대해 검증하는 것에 있다. 이에 본 연구는 국내 100인 이상 기업에 종사하는 여성 중간관리자 3.076명을 대상으로, 일-삶 균형(WLB)이 관계지향 리더십에 미치는 영향을 조직공정성 매개와 최고경영자(CEO) 성평등인식의 조절된 매개 효과를 통해서 규명하였다. 데이터는 여성관리자패널 3차년도 자료를 활용하였고, PROCESS Macro(Model 14)로 조절된 매개모형을 추정하였다. 신뢰구간 추정을 위해 부트스트래핑5,000회와 Johnson–Neyman 기법을 병행하였다. 첫째, WLB는 관계지향 리더십에 유의한 정(+)의 직접효과를 보 였다. 둘째, 조직공정성의 단순 매개효과는 통계적으로 유의하지 않았다. 셋째, CEO 성평등 인식은‘조직 공정성 → 관계지향 리더십’경로를 유의하게 조절하였으며, CEO 성평등 인식이 낮은 조건에서는 효과가 약화(또는 부적)되고 높은 조건에서는 강화되는 양상이 확인되었다. 조절된 매개효과 지수는 유의하였다. 이러한 결과는 WLB가 제공하는 심리·인지적 자원이 조직공정성 만으로는 자동적으로 리더십 행동으로 전이되지 않으며, 최고경영진의 성평등 가치와 톤-앳-더-탑(Tone at the top)의 신호가 존재할 때 공정성 이 관계지향 리더십으로 연결됨을 시사한다. 이러한 결과를 종합하여 이론 및 실무적 시사점, 한계점과 후속연구의 방향에 대해 논의하였다.

This study presents the results of compression, drop impact, and vibration durability analyses conducted to evaluate the mechanical reliability of Battery Pack Cases (BPCs) in electric vehicle (EV) systems. BPCs are essential structural components that must endure compressive loads, impact forces, and vibrational fatigue. Finite Element Analysis (FEA) was applied to a representative BPC model to assess deformation, impact resistance, and vibration endurance. The results indicate that the BPC maintained integrity within yield strength limits under compressive loading and effectively absorbed energy under drop impact. Furthermore, Power Spectral Density (PSD) analysis identified stress concentration regions, providing insights for structural optimization. Overall, the findings support the development of lightweight and reliable BPC designs for advanced EV applications.

Ear clamps are components used to securely fasten pipes and hoses in various industrial applications. They achieve clamping force by inducing plastic deformation at the ear region during installation, which can lead to accumulated structural damage and affect fatigue life. Moreover, the fatigue life is influenced by the design shape of the ear. Therefore, in this study, tensile and fatigue tests were conducted on two types of ear clamps with different ear geometries. Finite element analysis (FEA) was performed to obtain the stress distribution around the ear region, and these results were correlated with the experimentally obtained fatigue life. Based on this correlation, an S-N curve for simulation-based fatigue life estimation was established. This approach confirms the possibility of predicting the fatigue life of ear clamps with modified geometries using only finite element analysis, without the need for repeated fatigue testing.