This study aims to develop and evaluate a GPT-based English learning system that creates reading materials tailored to the Korean middle school first-grade English curriculum. To this end, this study adopted OpenAI’s MyGPTs platform and created the AI system through eight different developmental versions by iterating prompts and uploading relevant knowledge files. To evaluate its linguistic appropriateness, this study generated reading passages at three difficulty levels (low, medium, high) and compared them with eight textbook texts using seventeen key indices from Coh-Metrix 3. The results show that GPT-generated texts at the medium level most closely resembled actual textbook passages in sentence count, syntactic simplicity, lexical familiarity, and overall readability. Low-level outputs achieved the highest readability and concreteness scores, indicating suitability for beginner EFL learners, while high-level outputs featured greater syntactic complexity, longer sentences, and richer lexical diversity. The study also identified limitations in GPT’s consistent adherence to prescribed difficulty parameters, text-type variety, and adaptive difficulty adjustment based on learner performance.

This paper proposes an Adjustable Circular Steel Connector(ACS) to enable immediate response to construction errors that may occur during the on-site assembly of modular members. To evaluate its flexural performance, one rectangular steel tube beam specimen without ACS and three specimens with ACS(with varying ACS lengths) were fabricated. Experimental results showed no pull-out occurred between Shank A and Shank B, and the application of ACS facilitated stress distribution in the rectangular steel tube. The specimens with ACS exhibited up to 92% of the maximum load capacity of the monolithic specimen, and showed increasingly ductile behavior as the ACS length increased. Due to the cross-sectional difference between Shank A and Shank B within the ACS, yielding was observed in Shank B. Further studies are needed on this part, as well as on the behavior of the ACS under cyclic loading conditions.

본 연구에서는 실험실 규모의 혈액투석 실험 장치를 구성하고 polysulfone (PS) 중공사막과 polyethylene terephthalate (PET) 소재의 모노 및 멀티 스페이서 얀(spacer yarn)을 적용한 5 종류의 소형 혈액투석 모듈을 제작하여 스페이서의 존재가 혈액투석 모듈에 미치는 영향을 확인하였다. 수투과도 측정 결과에서 스페이서가 없는 모듈의 flux가 가장 높은 것으 로 확인되었으나, 이는 스페이서를 적용한 모듈의 막표면적이 감소한 원인으로 분석된다. 반면, 요소(urea) 제거 실험에서는 스페이서 적용 여부와 종류에 따른 성능 차이가 뚜렷하게 나타났으며, 스페이서가 내부 유동 균일화에 기여함으로써 확산 저 항을 감소시키는 효과가 확인되었다. 특히 모노 스페이서를 10 wt% 적용한 모듈은 낮은 막표면적에도 불구하고 혈액투석 실 험 3 h 경과 시점에서 약 67.99%의 요소 제거율을 기록하여, 스페이서를 적용하지 않은 모듈(62.75%) 대비 약 5.24% 높은 요소 제거 효율을 나타냈다.

본 연구에서는 α-Al2O3 중공사 지지체 위에 γ-Al2O3, SiO2 산화막 및 Pd 금속막을 각각 증착하여 수소 분리막을 제작하고, 암모니아 열분해 반응 후 생성되는 혼합기체(H2, N2, NH3)에 대한 투과 성능을 비교⋅분석하였다. scanning electron microscope과 atomic force microscope 분석 결과, 산화막 코팅을 통해 표면 조도가 크게 개선되어 Pd 무전해도금 시 결 함 억제에 기여할 수 있음이 확인되었다. 기체투과실험은 450°C, 0.5~2.0 barg 조건에서 수행되었으며, 산화막 기반 분리막은 기공 투과 메커니즘에 의해 최대 수소 순도가 82%에 머무른 반면 금속막 기반 분리막은 용해–확산 기반의 bulk diffusion 메 커니즘을 통해 97% 이상 순도의 수소를 안정적으로 분리하였다. 특히 Pd/α 중공사막은 2 barg에서 15 mL/min 이상의 수소 flux와 1900 이상의 H2/NH3 seperation factor을 기록하며 산화물 기반 분리막보다 월등한 성능을 보였다. 결론적으로 산화물 막은 단독 분리 성능은 제한적이지만 Pd 증착을 위한 전처리 및 중간층으로서 유효함이 확인되었으며, Pd 중공사막은 고온 수소 정제 공정에 가장 적합한 선택지임을 입증하였다.

This study was conducted to improve the stability of small barges used for remote bird monitoring at Capsosiphon fulvescens aquaculture farms. The monitoring accuracy is compromised by rolling and pitching motions induced by waves and wind. To address this problem, a damping system was developed to enhance barge stability. Field experiments were conducted at a farm to evaluate the effectiveness of the developed damping system. The rotational motions of the barge, with and without the damping system, were measured using a six-axis gyroscope sensor. The measurements were conducted at the Capsosiphon fulvescens farm located in Cheokchan-ri and Deokdong-ri, Gogeum-myeon, Wando-gun, Jeollanam-do across two periods: from October 5, 2024 to December 17, 2024 (Damping without) and from February 19, 2025 to April 15, 2025 (Damping with). The collected data were validated against wind speed records from the Korea Meteorological Administration. The results demonstrated that the damping system effectively reduced barge motion. Within a wind speed range of 0.1-9.0 m/s, the system achieved an average reduction of 7.11% in rotational motions. Its maximum performance was recorded at approximately 7.0 m/s wind speed where it achieved a reduction of 23.35%. These findings confirm the system significantly enhances barge stability and improves monitoring reliability.

Current seismic design provisions prohibit the use of a weak panel zone from using special moment frame (SMF) connections due to concerns that large deformations in these zones may lead to brittle connection failures. However, several experimental studies have demonstrated that moment connections with weak panel zones can exhibit adequate ductility and energy dissipation capacity for SMF connections. This study aims to investigate the impact of weak panel zones on the seismic performance of SMFs utilizing welded unreinforced flange-welded web (WUF-W) connections, as outlined in AISC 358-22. The analysis will consider both four-story and twelve-story SMFs. Each frame will be modeled with either strong or weak panel zones. The findings indicate that SMFs with weak panel zones demonstrate greater ductility and collapse strength compared to their counterparts with strong panel zones.

This study compared the physical properties and catch performance of gillnets made from biodegradable PBEAS (butylene succinate-co-adipate/terephthalate-co-ethylene succinate) resin with those of conventional PA (polyamide) gillnets in coastal gillnet fisheries targeting Pampus argenteus. Mechanical tests showed that PBEAS nets showed tensile strength and elongation similar to PA nets. In field trials, the total catch weight of PBEAS nets (596.6 kg, 261 individuals) was slightly higher than that of PA nets (535.1 kg, 248 individuals). The catch of Pampus argenteus was also greater in PBEAS nets with increases of approximately 51.0% in number and 35.8% in weight although the difference in total catch weight between the two net types was not statistically significant (Wilcoxon signed-rank test, p = 0.25). The size distribution of Pampus argenteus ranged from 12 to 28 cm fork length (FL) for both nets, with PBEAS nets showing more individuals particularly in the 16 – 20 cm range. Bycatch patterns were similar between the two gears where Chelidonichthys kumu, white Argyrosomus argentatus, and Zeus faber identified as dominant species. These findings clearly demonstrate the practical potential of PBEAS biodegradable gillnets and highlight their promise as an alternative to PA nets for promoting sustainable fisheries.

바다의 사막화라 할 수 있는 갯녹음(barren ground)은 우리나라뿐만 아니라 미국, 일본 등 전세계적으로 발생하여 수산생물의 서식지 황폐화, 해양 탄소고 정 능력 약화, 해양생태계 순기능 상실이라는 부정적 영향을 미치고 있다. 갯 녹음의 발생원인은 기후변화, 해수온도 상승, 해양 산성화, 이산화탄소, 지하수, 조식동물, 해양오염 등 복합적인 요인으로 추정하고 있으나 현재까지는 정 확한 원인을 규명하지 못하고 있다. 갯녹음 대응을 위해 우리나라는 바다숲(marine forests) 조성사업을 시행하 고 있지만 갯녹음이 왜 발생하는지에 대한 원인을 명확하게 규명하지 못한채 사업이 진행되다 보니 갯녹음 발생이 줄어들지 않고 있다. 본 연구는 갯녹음의 유발요인을 찾기 위해 현재 해양환경관리를 위한 지표 (indicator)와 지수(index)를 살펴보고 바다숲 조성사업 시행에서 나타난 바다숲 조성사업 시행지침상의 평가항목, 천연 해조장 등급화상의 평가항목, 갯녹음의 진단 및 판정 기준상의 평가항목을 검토하고 이들 지표 및 지수에서 갯녹음 관 리를 위한 지표와 지수의 개발 방향에 대해 검토하였다.