This study develops a Skip-Connected Temporal Contextual Deep Learning (SC-TCDL) model to forecast monthly inbound foreign tourist arrivals to South Korea, targeting demand volatility and structural shocks such as COVID-19 while supporting planning-oriented decision making. SC-TCDL adopts a dual-stream architecture that disentangles inputs by function: an LSTM branch encodes a 12-month rolling history of arrivals with calendar indicators, while an encoder-only Transformer processes forward-looking exogenous variables with positional encodings. The LSTM temporal representation is injected into the Transformer and fused with the Transformer output via an MLP through skip connections. COVID-period distortion (Mar 2020 Dec 2023) is addressed by virtual demand restoration using a counterfactual LSTM trained on pre-pandemic data. Probabilistic forecasts are generated via Monte Carlo Dropout. Using monthly data (Feb 2013 Apr 2025), SC-TCDL outperforms SARIMA, vanilla LSTM, and a Transformer on the test period (May 2024 Apr 2025), achieving MAE 78,626, RMSE 94,019, and MAPE 6.94%, reducing MAE by 30.5% relative to SARIMA, 28.3% relative to vanilla LSTM, and 24.9% relative to the Transformer, with statistically significant improvements by Wilcoxon signed-rank tests. By structurally separating temporal and contextual learning while enabling controlled fusion and uncertainty quantification, SC-TCDL offers a robust framework for tourism demand forecasting in shock-prone environments.

This study aims to refine the existing shear strength model for reinforced concrete(RC) beam–column connections by explicitly incorporating the bi-directional loading effect, which more accurately reflects the actual loading conditions of RC structures during earthquakes. A new database consisting of 21 RC beam–column connection specimens tested under simultaneous bi-directional loading was collected and analyzed to investigate the influence of key parameters on joint shear strength. The results revealed that the joint configuration and the presence of a slab are the primary factors governing the extent of bi-directional loading effect on joint shear strength. Based on these findings, a set of simple and practical modification factors was proposed to refine the existing joint shear strength model to account for bi-directional loading effect. The outcomes of this study provide a rational basis for incorporating bi-directional loading effect into the shear strength evaluation of RC beam–column connections

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.

본 연구는 온실 구조에서 서까래–도리 접합부의 반강 접(semi-rigid) 거동을 실험적으로 규명하고, 해석 모델 (GHModeler)의 적용 타당성을 검증하기 위하여 수행되었다. 시중에서 사용되는 선형 죔쇠를 이용하여 교차부 실험체를 제 작하고, 6 자유도 변형 모드에 대한 강성 계수와 항복 특성을 평가하였다. 서까래가 도리 축을 따라 미끄러질 때 강성 계수 243,228.92 N·m-1, 항복 하중 164 N으로 가장 크게 나타났으 며, 도리가 서까래 축을 따라 미끄러질 때는 각각 30,426.78 N·m-1, 118 N으로 현저히 낮은 값을 보였다. 회전 및 비틀림 모드에서도 뚜렷한 차이를 확인하였다. 이어서 실물 규모의 단동 온실을 대상으로 횡하중 재하 시험을 실시하고, 변위 및 응력 거동을 GHModeler 해석 결과와 비교·분석하였다. 비교 결과, 수평 변위(DH2)에서 강접합 모델은 최대 310.2% 오차 를 보인 반면, 인터페이스 요소 모델은 －13.7%~34.1% 범위 로 감소하였다. 응력(S1)에서도 강접합 모델은 최대 84.6%의 오차를 보였으나, 인터페이스 요소 모델은 －9.1%~3.2%로 실험치에 근접하였다. 본 연구 결과는 온실 구조물의 접합부 모델링 및 구조 안전성 평가의 신뢰성을 향상시키는 데 기여할 수 있을 것으로 기대된다.

This study investigates the seismic performance of beam-column connections using Thin-Walled Steel Composite (TSC) beams and Prestressed Reinforced Concrete (PSRC) columns. TSC beams are constructed from U-shaped thin steel plates that are filled with concrete, allowing for composite action with slabs through the use of shear connectors. They are widely applied in industrial buildings due to excellent strength, stiffness, and constructability. However, slender web plates are prone to local buckling, which may compromise their performance during seismic events. To mitigate this issue, internal supports have been introduced to enhance web stability and concrete confinement. Cyclic loading tests on three specimens—with and without internal supports—demonstrated that the supports increased moment capacity, improved energy dissipation, and effectively reduced buckling. Even slender sections demonstrated performance comparable to that of compact sections. All specimens reached peak strength at a 2.44% rotation angle, with damage localized near the supports. A practical connection detail was also proposed, taking into account constructability and structural reliability. The results provide valuable guidance for the seismic design of composite systems in large-scale structures.

Reinforced concrete (RC) moment frames are widely used to resist lateral loads associated with wind and earthquakes. However, most older RC moment frames performed poorly against past earthquakes. In moment frames, beam-column connections play a crucial role in system performance. Among the connections, corner connections are more vulnerable because they are restrained by only two beams and are affected most strongly by bidirectional loading. High-performance fiber-reinforced cementitious composites (HPFRCC) were used in previous studies to improve the seismic performance of older beam-column connections. This study aims to evaluate the level of improvement of seismic behavior of older beam-column connections under bidirectional loading after retrofitted with HPFRCC by comparing the seismic behavior of the HPFRCC connections to beam-column connections used in intermediate (IMF) and special moment frames (SMF). Test results revealed that the seismic behavior of the HPFRCC connections was almost close to that of SMF connections.

본 연구에서는 센싱 기반 모니터링 스마트 파이프 개발 연구의 일환으로 화학적 전처리된 코팅 강관에 대한 유한요소해석을 실시 하였다. 개발된 코팅 강관은 내･외면 개질 폴리에틸렌으로 화학적 코팅 전처리 과정을 수행하였으며, 확관 시 표면 코팅 손상을 최소 화하기 위한 연결 부속을 사용한 코팅 강관의 해석을 수행하였다. 다양한 하중에 대한 구조성능 평가를 위해 토압 하중에 의한 정적 구 조해석, 차량 하중에 의한 피로수명 평가, 인장 및 압축 하중에 의한 누수 저항성의 4가지 하중 조건을 설정 및 조사하였다. 해석 결과, 기존 에폭시 코팅 및 조인트 사용 강관 대비 개발 강관에서 개선된 피로 수명이 산출되었으며, 동일 직경의 조건에서 평균 56.1%의 최 대 변위 감소와 61.2% 최대 응력이 감소함을 통해 개발 코팅 강관과 연결 부속의 안전성을 검증하였다. 이에 더하여 응력 분포 분석을 통해 체결부의 누수 저항성 역시 강관 중앙면 대비 우수함을 확인하였다.

In this study, the SBC system, a new mechanical joint method, was developed to improve the constructability of precast concrete (PC) beam-column connections. The reliability of the finite element analysis model was verified through the comparison of experimental results and FEM analysis results. Recently, the intermediate moment frame, a seismic force resistance system, has served as a ramen structure that resists seismic force through beams and columns and has few load-bearing walls, so it is increasingly being applied to PC warehouses and PC factories with high loads and long spans. However, looking at the existing PC beam-column anchorage details, the wire, strand, and lower main bar are overlapped with the anchorage rebar at the end, so they do not satisfy the joint and anchorage requirements for reinforcing bars (KDS 41 17 00 9.3). Therefore, a mechanical joint method (SBC) was developed to meet the relevant standards and improve constructability. Tensile and bending experiments were conducted to examine structural performance, and a finite element analysis model was created. The load-displacement curve and failure pattern confirmed that both the experimental and analysis results were similar, and it was verified that a reliable finite element analysis model was built. In addition, bending tests showed that the larger the thickness of the bolt joint surface of the SBC, the better its structural performance. It was also determined that the system could improve energy dissipation ability and ductility through buckling and yielding occurring in the SBC.

This study addresses the scarcity of research examining technology’s impact on learners of English as a foreign language in English for specific purposes (ESP) courses within English-medium instruction (EMI) programs. Focusing on a business communication course using a social question-answering platform, this study explores the interplay among English proficiency, motivational orientations, and online engagement. Surveying 126 university students via a mixed-method approach, this research identifies distinct motivational orientations (intrinsic, extrinsic, and self-efficacy) existing during class activities, influenced by proficiency levels, with notable differences in online participation between beginner and advanced learners. The findings suggest that while online activities enhance peer interaction and teacher feedback, they may trigger anxiety in beginners, potentially diminishing motivation and self-efficacy. These results emphasize the need to tailor technology integration to proficiency levels and motivational orientations in ESP/EMI settings. Practical recommendations are offered for educators aiming to implement effective online activities and provide targeted support, particularly for beginner learners, thereby bolstering their motivation and selfefficacy.

For fast-built and safe precast concrete (PC) construction, the dry mechanical splicing method is a critical technique that enables a self-sustaining system (SSS) during construction with no temporary support and minimizes onsite jobs. However, due to limited experimental evidence, traditional wet splicing methods are still dominantly adopted in the domestic precast industry. For PC beam-column connections, the current design code requires achieving emulative connection performances and corresponding structural integrity to be comparable with typical reinforced concrete (RC) systems with monolithic connections. To this end, this study conducted the standard material tests on mechanical splices to check their satisfactory performance as the Type 2 mechanical splice specified in the ACI 318 code. Two PC beam-column connection specimens with dry mechanical splices and an RC control specimen as the special moment frame were subsequently fabricated and tested under lateral reversed cyclic loadings. Test results showed that the seismic performances of all the PC specimens were fully comparable to the RC specimen in terms of strength, stiffness, energy dissipation, drift capacity, and failure mode, and their hysteresis responses showed a mitigated pinching effect compared to the control RC specimen. The seismic performances of the PC and RC specimens were evaluated quantitatively based on the ACI 374 report, and it appeared that all the test specimens fully satisfied the seismic performance criteria as a code-compliant special moment frame system.

Modular construction is an economical and efficient construction that reduces time and costs by manufacturing units in factories and constructing them on site. Currently, the demand for modular construction is increasing not only abroad but also domestically. As the demand for modular construction increases, a lot of development and research on connections between modular units are being conducted. Connections between modular units should be quick and simple to assemble when assembling units on site, and should be in a form that allows each unit to be connected regardless of direction. In addition, it must be able to exert sufficient strength against external loads. In this study, a connection between modular units using connecting steel plates and bolts was proposed, and the nonlinear behavior of the connection to external lateral force was analyzed through finite element analysis, and resistance performance was evaluated.

This study presents a dry precast concrete (PC) beam-column connection, and its target seismic performance level is set to be emulative to the reinforced concrete (RC) intermediate moment resisting frame system specified in ACI 318 and ASCE 7. The key features include self-sustaining ability during construction with the dry mechanical splicing method, enabling emulative connection performances and better constructability. Test specimens with code-compliant seismic details were fabricated and tested under reversed cyclic loading, which included a PC beam-column connection specimen with dry connections and an RC control specimen. The test results showed that all the specimens failed in a similar failure mode due to plastic deformations in beam members, while the hysteretic response curve of the PC specimen showed comparable and emulative performances compared to the RC specimen. Seismic performance evaluation was quantitatively addressed, and on this basis, it confirmed that the presented system can fully satisfy all the required performance for the intermediate RC moment resisting frame.

The column-tree type steel beam-column connections are commonly used in East Asian countries, including Korea. The welding detail between the stub beam and column is similar to the WUF-W connection; thus, it can be expected to have sufficient seismic performance. However, previous experimental studies indicate that premature slip occurs at the friction joints between the stub and link beams. In this study, for the accurate seismic performance evaluation of column-tree type moment connections, a moment-slip model was proposed by investigating the previous test results. As a result, it was found that the initial slip occurred at about 25% of the design slip moment strength, and the amount of slip was about 0.15%. Also, by comparing the analysis results from models with and without the slip element, the influence of slip on the performance of overall beam-column connections was examined. As the panel zone became weaker, the contribution of slip on overall deformation became greater, and the shear demand for the panel zone was reduced.