https://doi.org/10.12652/Ksce.2026.46.5.0395

박범준(Park, BumJun) ; 방건혁(Bang, GeonHyeok) ; 이재훈(Lee, JaeHoon) ; 허광희(Heo, GwangHee) ; 전승곤(Jeon, SeungGon)

In this study, an integrated data mining approach was proposed for the efficient extraction and management of vehicle load information from real-time strain responses measured using an energy-based Enhanced Bridge Weigh-In-Motion (EnBWIM) system. From the continuously acquired raw EnBWIM data, vehicle passage events were detected and valid response segments were selectively extracted. Strain-energy-based analysis was then performed to obtain vehicle management information, including gross vehicle weight, axle loads, axle spacing, and traveling speed. In addition, identification information, such as vehicle license plate number, passage time, and speed, was extracted from raw data independently acquired using a high-speed (HS) camera and a speed gun and subsequently linked with the corresponding EnBWIM measurements. Data obtained from the different measurement devices were synchronized based on time information, enabling the management and identification information associated with the same vehicle to be integrated. Application of the proposed data mining approach to 24-h continuous monitoring data demonstrated that approximately 99 % of the raw data could be reduced by retaining only the essential information required for overweight vehicle management, thereby significantly improving data storage and processing efficiency. Furthermore, a relational database management system (RDBMS) was developed by integrating the extracted management and identification information to systematically store and retrieve the passage history of individual vehicles. The developed database enables integrated management of gross vehicle weight, axle loads, license plate number, passage time, traveling speed, and axle spacing for individual overweight vehicles. The proposed EnBWIM-based integrated data mining and database framework can therefore facilitate the efficient processing of large-scale continuous monitoring data and long-term tracking of overweight vehicle passage histories. The resulting information can also provide a useful basis for bridge maintenance, assessment of cumulative load effects induced by overweight vehicles, and the development of proactive risk management strategies.

https://doi.org/10.12652/Ksce.2026.46.5.0407

김서영(Kim, Seoyoung) ; 신주영(Shin, Ju-Young) ; 권지혜(Kwon, Jihye) ; 최소영(Choi, Soyoung)

Recent climate change has increased the frequency and risk of flooding, further emphasizing the importance of maintaining aging river infrastructure. In Korea, many river facilities were intensively constructed between the 1970s and 1990s, and as their service periods increase, systematic performance management and maintenance strategies are required to ensure public safety and extend facility service life. In this study, survival analysis was applied to historical safety-grade records to examine performance deterioration and the timing of the first occurrence of Grade C for levee facilities in Korea. Facilities that did not reach Grade C during the observation period were treated as right-censored data to minimize information loss. Kaplan-Meier estimation showed that 10 % of the facilities reached Grade C at 42.0 years. Among 1,499 facilities, only 42 cases (2.8 %) reached Grade C, and therefore the median time to the first Grade-C transition could not be estimated from the observed data. To investigate long-term performance changes, four probability distributions were fitted, and the Weibull distribution was selected as the best-performing model. Under the Weibull model, the times at which 10 % and 20 % of facilities were expected to reach Grade C were estimated as 46.6 and 74.4 years, respectively, while the median time to the first Grade-C transition was estimated as 150.8 years. However, because the 150.8-year estimate is an extrapolated long-term model result rather than an observed value, it should be interpreted with caution and reassessed when additional long-term inspection data become available. The findings can provide quantitative reference information for determining maintenance timing, prioritizing levee facilities, and allocating limited maintenance budgets more efficiently.

https://doi.org/10.12652/Ksce.2026.46.5.0417

이정우(Lee, Jeongwoo)

The objective of this study is to evaluate the effects of the simplifying assumptions incorporated in Baalousha’s analytical solution and to assess its applicability for estimating groundwater drawdown and streamflow depletion from a finite-width stream induced by groundwater pumping. Baalousha’s analytical solution has the advantage of separately analyzing groundwater-level changes caused by groundwater pumping and stream leakage based on the principle of superposition, thereby allowing their respective effects to be evaluated. However, the solution involves several simplifying assumptions, including that the groundwater-level change induced by stream leakage is symmetrically distributed with respect to the stream center and that, under quasi-steady conditions, diffusion is considered only in the transverse direction. Therefore, in this study, Baalousha’s analytical approach was extended and reformulated as a boundary-value problem for two-dimensional transient groundwater flow without assuming symmetry in the groundwater-level change induced by stream leakage. An analytical model was developed by applying Fourier and Laplace transforms, followed by numerical inverse transforms to determine groundwater drawdown and streamflow depletion in the time and spatial domains. The developed model was applied under various hydraulic and geometric conditions, including transmissivity, storativity, streambed hydraulic conductivity, stream width, and stream-well distance, and the results were compared with Baalousha’s analytical solution. The results showed that, under relatively low aquifer hydraulic diffusivity, the difference between the two solutions tended to increase with stream width. In particular, comparison of streamflow depletion ratios in terms of the dimensionless characteristic time, defined using time, the stream depletion factor, and relative distance, showed that when the dimensionless characteristic time exceeded 5, Baalousha’s solution yielded results similar to the present solution, which accounts for asymmetric groundwater-level changes induced by stream leakage and two-dimensional transient groundwater flow.

https://doi.org/10.12652/Ksce.2026.46.5.0433

황석환(Hwang, Seokhwan)

The Yongin semiconductor megacluster will require about 764,000 t/day of industrial water and more than 15 GW of power at full operation, and even after the integrated water-supply project a deficit of about 1,072,000 m³/day of industrial water (1,097,000 m³/day including municipal water) is projected by 2050. Where both power and water jointly govern feasibility, the conventional site-first approach, which fixes large facilities first and fits infrastructure afterwards, is structurally inadequate. This study inverts that order, locating and sizing clusters by the joint carrying capacity of the energy and water systems. The core method is a non-compensatory co-limiting aggregation reflecting the physical non-substitutability of power and water (Liebig's law of the minimum), so the smaller resource governs capacity. Water is treated as a hard hydrological constraint rather than mere proximity. The reservoir firm-yield reliability model is used to project how dam-level firm yield responds to the SSP signals; for the site-level water input, however, the published dam supply capacities of K-water are used rather than firm yield re-estimated from observed inflow series. Future availability is assessed by taking the reported annual-precipitation change (+21.5?38.7 %) of the Korea 1 km SSP scenarios, produced by the National Institute of Agricultural Sciences (NIAS, Rural Development Administration) and certified by the KMA as the 2022 national standard (CMIP6 18-GCM; Heo et al., 2024), as input, translating it to runoff change by streamflow elasticity, and propagating inter-model spread and drought intensification by Monte Carlo. Suitability is evaluated under three lenses, present readiness, alternative potential via resource linkage, and future availability, and synthesised by a weighted geometric mean (partially non-compensatory), cross-checked with TOPSIS and SMAA rank-acceptability. Applied to real geometry with real published lifeline data (K-water dam supply capacities; 2023 regional power statistics), the binding constraint partitions cleanly into energy-binding (Han basin) and water-binding (south) sites, and an asymmetry in linkage feasibility, energy readily relieved by grid reinforcement and water hardly by inter-basin transfer, governs relative suitability. A constraint-relief analysis shows that power-rich coastal water-scarce sites can desalinate surplus power to make up the water shortfall, expanding the cluster up to the size at which power, rather than water, becomes the limit (Saemangeum 2.6 → ~12.8 GW).

https://doi.org/10.12652/ksce.2026.46.5.0449

채규종(Chae, Gyu Jong) ; 정민주(Jeong, Min Ju) ; 오현주(Oh, Hyun Ju) ; 박형춘(Park, Hyung Choon)

Compaction quality control of embankment soils in Korea is mainly conducted using the field density test (KS F 2311) and plate bearing test (KS F 2310). However, these methods have limitations in providing rapid quality control because of constraints related to test procedures and equipment operation. This study evaluated the degree of compaction of embankment soils using two nondestructive testing methods: the elastic modulus (Eg) measurement using a GeoGauge and the impact factor (Ia) measurement using CASPFOL, and examined their field applicability by comparison with conventional tests. Tests were conducted at the Dongtan model test site, the Sejong 5-1 Residential Area field verification site, and a homogeneous ground test site with a uniform particle-size distribution. In the model tests, Eg and Ia generally increased with the number of compaction passes, reflecting changes in the compaction state of the ground. In the field verification tests, Eg showed a relatively high correlation with relative compaction and stable measurements even in heterogeneous embankment materials. In contrast, Ia was strongly affected by particle-size distribution and showed large variability in heterogeneous ground. In the homogeneous ground tests, the variability of repeated measurements decreased for both Eg and Ia, with Ia showing particularly stable results. These results indicate that Eg can complement conventional compaction evaluation tests as a rapid quality-control method, whereas Ia can provide more reliable compaction evaluation in ground with a uniform particle-size distribution, such as dredged fills.

https://doi.org/10.12652/Ksce.2026.46.5.0459

최태정(Choi, Taejeong) ; 박진우(Park, Jinwoo) ; 김정화(Kim, Junghwa)

This study defines dynamic accessibility based on temporal variations in bus-to-subway transfer time using Seoul transportation card data, analyzing 15 major transfer stations served by three or more intersecting urban railway lines. A transfer time gap indicator?representing each time period's deviation from the station's daily average?was developed as a dynamic accessibility measure. K-means clustering was applied to classify the 15 stations into three distinct types: stable stations with minimal gap variation and faster-than-average transfers during morning peak hours; mixed stations exhibiting the largest morning peak gap reduction but high overall temporal variability; and sensitive stations showing markedly larger transfer time gaps during off-peak hours. Pearson correlation analysis revealed a statistically significant positive association between commercial land-use ratio within each station's catchment area and off-peak transfer time gaps, and this association remained stable even after excluding a station with an exceptionally high commercial ratio. These findings suggest that surrounding land-use characteristics are meaningfully associated with temporal variations in transfer accessibility. Specifically, commercially dominant catchment areas appear to attract more non-commute trips during midday hours, which may be associated with elevated off-peak transfer times and reduced dynamic accessibility. The findings support the need for time-differentiated, station-type-specific transfer management strategies tailored to each cluster's characteristics. This approach also demonstrates the practical potential of transportation card data as a low-cost, continuously available tool for monitoring dynamic transfer accessibility across urban rail networks without requiring additional field surveys.

https://doi.org/10.12652/Ksce.2026.46.5.0471

김병일(Kim, Byungil) ; 정도범(Chung, Do-Bum) ; 백승원(Baek, Seungwon)

This study analyzes revenue growth patterns before the issuance of modified audit opinions in Korean construction firms and examines differences between firms receiving disclaimers of opinion and those receiving qualified opinions. Financial statement data were collected from 398 construction firm cases whose audit opinions changed from unmodified opinions to either disclaimers of opinion or qualified opinions between 2009 and 2024. Year-over-year revenue growth rates over the five years preceding the opinion year were compared across groups using t-tests and panel regression tests accounting for firm-level clustering, and excess growth rates relative to same-year unmodified-opinion group means were examined to account for year-specific market conditions. The results show that firms receiving disclaimers of opinion exhibited a boom-and-bust pattern, in which revenue increased sharply three to four years before the audit opinion year and then declined steeply as the opinion year approached. In contrast, firms receiving qualified opinions showed lower revenue volatility and tended to maintain or recover a certain level of revenue immediately before the opinion year. Firms with lower interest coverage ratios displayed more pronounced early revenue increases and subsequent declines. The boom-and-bust pattern of disclaimer firms was statistically significant: their revenue growth significantly exceeded same-year unmodified-opinion means three to four years before the opinion year and fell significantly below them immediately before it, whereas qualified-opinion firms did not differ significantly from unmodified-opinion firms in any period. These findings suggest that abnormal revenue fluctuations in construction firms can serve as early warning information for identifying the severity of financial distress.

https://doi.org/10.12652/Ksce.2026.46.5.0485

홍철승(Hong, Chulseung) ; 이수연(Lee, Suyeon) ; 문창(Moon, Chang) ; 은영기(Eun, Youngkee)

The Korean Design Standards (KDS) specify technical requirements for the design of various types of infrastructure and construction works. In engineering practice, engineers must not only locate relevant clauses but also identify the values or provisions applicable to the conditions at hand and verify their supporting basis. However, this review still relies largely on manual examination, and document search alone makes it difficult to select provisions applicable to conditions expressed in natural language and to determine whether a generated answer is supported by the source text. This study proposes EC-RAG (Engineering Code RAG), a system that interprets the conditions stated in a natural-language query, retrieves relevant evidence from the full KDS corpus, presents a condition-specific answer with a supporting quotation, and checks whether the answer value is supported by that quotation. Clause-path information and textual representations of tables and formulae were extracted from the KDS source documents to construct retrieval units, and keyword-based retrieval was combined with semantic similarity retrieval. The system was also designed not to present an answer value as definitive when it could not be confirmed from the retrieved evidence. Approximately 50,000 retrieval units were constructed from 568 KDS documents collected at the time of data acquisition, and the system was evaluated using 1,019 questions spanning 18 major KDS categories. The evaluation queries did not include a specific KDS code or clause path, and the system searched the full index for each query. The final answer accuracy was 97.7 % (996/1,019). Of the 23 questions not judged correct, 19 resulted from difficulties in identifying the applicable value in multi-level tables, while four resulted from the relevant evidence not being included among the retrieved candidates. These results indicate that the proposed approach can support the identification of relevant design provisions and applicable values from natural-language queries without requiring users to specify a document or clause in advance. They also identify table-structure processing and retrieval performance as the main areas for further improvement.

https://doi.org/10.12652/Ksce.2026.46.5.0501

이석배(Lee, Suk Bae) ; 김광배(Kim, Kwang Bae) ; 곽희수(Kwak Hee Soo)

Underground facility surveying is a highly dangerous task that can lead to fatal accidents, such as death, making the institutionalization of safety management an urgent necessity. This study aims to institutionalize surveying safety to ensure the safety of surveyors at underground facility surveying sites. To this end, on-site inspections regarding risk assessment and safety management were conducted at two underground facility surveying sites, and the costs required for safety management were calculated directly. The results showed that the average risk score for underground facility surveying was 12.6 % higher than that for road facility surveying, confirming that safety management records and risk assessments must be performed at all underground facility surveying sites. Furthermore, to institutionalize surveying safety, the preparation of safety management plans must be made mandatory for all underground facility surveying sites; contractors must bear responsibility for compliance with these plans, and clients must bear the responsibility for supervision regarding adherence to the plans. It was concluded that safety management costs required for underground facility surveying sites must be secured at a rate equivalent to at least 5.64 % of (material costs + direct labor costs) per project. Furthermore, safety management training in accordance with the Industrial Safety and Health Act and pre-work safety training must be strengthened, and a safety culture must be fostered in the surveying industry where surveyors take responsibility for and protect their own safety.

https://doi.org/10.12652/ksce.2026.46.5.0511

(Yun, Konghyun) ; (Lee, Hanna) ; (Kim, Gihong)

Quantifying landslide-induced topographic change requires precise comparison of pre- and post-event terrain data. When the datasets differ in acquisition date, sensor type, spatial resolution, and positional accuracy, measurement error may be misinterpreted as real change. We reconstructed the pre-event terrain from 1:5,000 digital-map contours and spot heights using a triangulated irregular network (TIN), generated the post-event DTM from UAV LiDAR, and applied geomorphic change detection (GCD). Residual elevation differences over stable roads had a mean of -0.04 m and a standard deviation of 0.84 m; the mean vertical offset was therefore negligible relative to the dispersion. An empirical minimum level of detection (LoD) of 0.84 m was applied. After expanding the region of interest to include the source area and correcting the effect of fallen trees, erosion and deposition volumes were estimated as 105,391 m³ and 148,522 m³, respectively, yielding a net change of +43,131 m³. The workflow demonstrates how heterogeneous legacy and UAV-derived terrain data can be evaluated and used for reproducible landslide volume estimation when no high-resolution pre-event survey is available.

https://doi.org/10.12652/ksce.2026.46.5.0525

송영선(Song, YeongSun) ; 윤공현(Yun, Konghyun)

This study examined the association between road geometric characteristics and traffic accident risk-area designation on nationally supported provincial and provincial roads in Gyeonggi Province. Link-based traffic accident risk areas, the national standard node-link network, annual average daily traffic (AADT), and road-ledger data for 2020-2024 were integrated. For each representative risk-area link, non-risk links with similar AADT and link length on the same route and in the same year were matched, yielding 364 matched strata. The link-geometry-based curvature index was significantly correlated with the road-ledger density of curves with radii below 300 m (Spearman rho=0.657, p<0.001). In the primary conditional logistic model, the odds ratio (OR) per one-standard-deviation increase in the ln(1+C)-transformed and standardized curvature index was 1.217 (95 % CI 1.054-1.404, p=0.007), while the OR for number of lanes was 1.718 (p<0.001), indicating higher relative odds of risk-area designation among road sections with comparable traffic exposure and link length. However, a 2,000-resample cluster bootstrap weakened the evidence for the curvature index (percentile bootstrap 95 % CI 0.993-1.497; empirical p=0.062). The two representative-link assignment rules selected the same link for only 138 of 471 risk areas (29.3 %), and both curvature-index and lane estimates attenuated in the strictly common sample of 257 risk areas. These findings suggest a positive association between road geometry and risk-area designation while also demonstrating that the estimated magnitude and statistical precision are sensitive to spatial-linkage rules and sample composition.