목적: 한국 성인을 대상으로 세 가지 측정방법에 따른 평균 동공간거리를 제시하고 측정방식에 따른 차이를 평가하고 자 하였다 방법 : 숙련된 한명의 검사자가 세 가지 방법(PD 미터, PD 자, 자동안굴절력계)을 이용하여 단안 및 양안에서 원거리 동공간거리를 측정하였다. 정치는 평균±표준편차로 나타내었으며, Paired t-test를 이용하여 기기에 따른 측정값 평균의 차이를 비교하였다. Pearson correlation을 이용하여 측정방식 간 상관계수를 구하였으며, 두 기기 로 측정한 값의 일치도는 Bland-Altman plots 분석을 시행하여 95% 일치도 한계(일치도 하한, 일치도 상한)로 나타내었다. 결과 : 평균연령은 21±2.3세 이었으며, 성별은 남자가 47명(49.5%), 여자가 48명(50.5%)이었다. 세 가지 측 정 장비 모두 남자가 여자에 비하여 유의하게 컸다. 연구 대상자의 양안 평균 동공간거리는 PD 미터 62.53±3.22 mm, PD 자 63.16±3.29 mm, 자동안굴절력계 63.37±3.46 mm로 측정되었다. 대응표본 t검정을 이용하여 측정 방법에 따른 차이를 평가한 결과 PD 미터는 PD 자와 평균적으로 –0.64±2.84 mm의 차이를 보였고(p=0.031), 자 동안굴절력계와 평균적으로 -0.84±2.20 mm의 차이를 보였다(p<0.001). PD 자와 자동안굴절력계는 유의한 차이 를 보이지 않았다. 양안에서 95% 일치도 한계는 PD 미터와 PD 자가 –6.21∼4.93 mm, PD 미터와 자동안굴절력 계 –5.16∼3.47 mm, PD 자와 자동굴절력계 –6.49∼6.08 mm였다. 동공간 거리가 3.5 mm 이상 차이가 나는 경 우는 PD 미터와 PD 자가 18명(18.9%), PD 미터와 자동안굴절력계가 14명(14.7%), PD 자와 자동안굴절력계가 20명(21.1%)이었다. 결론 : 세 기기 간의 평균 차이는 모두 1 mm 이내로 임상적으로 유의한 수준의 불편을 유발하지 않는 범위로 판단되었으나 측정 방식에 따라 3.5 mm 이상 차이가 났던 14.7∼21.1%는 안경을 조제·가공하여 만들었을 때 측 정방식에 따른 오차로 인하여 시각적 불편 및 증상을 호소할 가능성이 있다.

Pavement friction under wet conditions is a critical factor affecting driving safety and is determined significantly by water-film thickness (WFT). Although current road geometric design standards incorporate wet-pavement friction coefficients as design parameters, they do not adequately account for the effects of WFT. This study estimates the variation in the coefficient of friction caused by changes in the WFT and applies the results to the calculation of stopping sight distance (SSD) and radius of curvature (RC), which are essential elements in road geometry design. Through this approach, the study identifies the limitations of current standards and proposes potential improvements. WFT was estimated using the Gallaway model, which was previously verified through comparative analysis and experimental validation. The model incorporates key influencing factors such as rainfall intensity, pavement slope, drainage path length, and mean texture depth. Based on the estimated WFT, the longitudinal and lateral friction coefficients were calculated using Gallaway’s SN and Lamm’s models, respectively. Using these friction values, the SSD and RC were evaluated under various pavement and environmental conditions. Furthermore, comparisons with existing design guidelines were performed to assess whether the predicted values satisfy the standards under different conditions. Additionally, areas requiring improvement were identified. The analysis confirmed that WFT increases with rainfall intensity and drainage path length, whereas it decreases as the pavement slope, mean texture depth, and tread depth increase. An increase in the WFT significantly reduces the friction coefficient, which consequently increases the SSD and required RC. In particular, under conditions such as heavy rainfall, worn treads, long drainage paths, and shallow surface textures, the calculated SSD and RC typically exceed the minimum requirements of current road-design standards. By contrast, ensuring sufficient surface texture effectively maintains friction performance and mitigates increases in the SSD and RC. The findings of this study suggest that current road-design standards—based on dry or vaguely defined wet conditions—may not sufficiently address the effects of WFT on pavement friction. A quantitative, WFT-based approach is required for more realistic friction estimations. To enhance safety in rainy conditions, road designs should incorporate structural and material improvements, such as optimizing pavement slopes, reducing the drainage path length, maintaining adequate surface texture and tread depth, and adopting high-performance surfacing materials. Additionally, dynamic speed-management systems during rainfall and preventive maintenance for sections with inferior drainage should be considered to improve driving safety under wet weather conditions.

본 연구는 S-O-R 모델에 기반하여, 한국 라이브커머스 인플루언서의 상호작용성이 중국 MZ세대 소비자의 구 매의도에 미치는 영향을 인지적 신뢰와 정서적 애착의 매개효과 및 문화적 거리의 조절 효과를 규명하고자 하였다. 한국 인플루언서의 라이브커머스 시청 경험이 있는 중국 MZ세대 소비자 239명의 데이터를 SPSS PROCESS macro를 활용하여 분석하였다. 실증분석 결과, 인플루언서 상호작용성은 인지적 신뢰와 정서적 애착을 유의하게 높였으며, 이 두 변수는 구매의도로 이어지는 경로를 완전 매개하는 것으로 나타났다. 하지만 예상과 달리, 문화 적 거리의 조절 효과는 유의하지 않았는데, 이는 인플루언서와의 상호작용을 통해 형성된 신뢰와 애착의 긍정적 효 과가 소비자가 느끼는 문화적 거리 수준과 관계없이 강력하게 작용함을 시사한다. 본 연구는 국경 간(cross-border) 라이브커머스에서 인플루언서의 상호작용성이 문화적 장벽을 넘어설 수 있는 핵심 동인임을 실증적으로 보여주었 다는 점에서 이론적 기여를 가진다. 또한 실무적으로는, 중국 MZ세대 공략 시 문화적 차이에 대한 우려를 넘어, 인플루언서와의 상호작용을 통한 신뢰와 정서적 애착 형성이 구매의도를 이끌어내는 가장 직접적이고 효과적인 경로임을 제시한다.

This study aims to validate the feasibility of using LiDAR reflectivity data to quantitatively estimate the retroreflectivity of road lane markings. The goal is to establish the optimal scanning conditions considering the channel position, angle of incidence, and vehicle speed for an accurate and consistent retroreflectivity assessment in mobile environments. Fifteen standard lane marking samples with known retroreflectivity values were scanned using an OS1-128 LiDAR sensor under controlled field conditions. A two-phase experiment was conducted: (1) a speed-based test to assess the influence of vehicle velocity (20-80 km/h) on LiDAR reflectivity measurements, and (2) a channel–angle–distance test using a static testbed to analyze the relationship between retroreflectivity, LiDAR channel position (that is, the angle of incidence), and measurement distance. Ground truth retroreflectivity values were obtained using a high-precision handheld retroreflectometer. Reflectivity measurements showed a strong correlation with standard retroreflectivity values, particularly at scanning angle between 100-115° and distances of 4.9-5.6 m. The coefficient of determination (R2) exceeded 0.97 across optimal conditions. Speedrelated tests confirmed that the LiDAR-based reflectivity remained stable with a minimal RMSE (< 5), even under high-speed driving scenarios. LiDAR sensors provided reliable and contactless estimates of pavement marking retroreflectivity when the channel angle and scanning distance were appropriately selected. The findings demonstrated that channel-specific calibration and incidence angle correction significantly improved the measurement accuracy. This suggests a practical path forward for automated large-scale retroreflectivity monitoring in road asset management systems.

This study analyzes the heterogeneous treatment effects of the COVID-19 pandemic on regional tourism demand in South Korea, focusing on the role of geographic distance from the metropolitan area to tourist destinations and the spatial characteristics of tourist destinations. Since a substantial portion of the population resides in the capital region, it can be expected that regional tourism demand is largely driven by residents of the capital region. In addition, the pandemic has particularly discouraged visits to indoor and densely populated areas due to increased perception of infection risk. To estimate these effects, we use a causal machine learning approach using double machine learning, analyzing monthly visitor data from 994 major tourist sites between the years 2019 and 2020. Tourist destinations are classified by spatial characteristics, including indoor, outdoor, and mixed settings as well as by tourism type. The analysis reveals that the impact of COVID-19 was more pronounced for indoor destinations located closer to the metropolitan center, whereas outdoor and mixed destinations showed little variation in treatment effects by distance. These findings highlight the importance of adopting distance-sensitive and space-specific policy measures in tourism planning during pandemics. Our study also demonstrates the practical utility of causal machine learning in tourism analytics, suggesting its potential for enhancing policy precision and resilience against future public health crises.

본 연구는 환경규제와 해외직접투자(FDI) 간의 관계를 재검토하고, 국가 간 거리(cross-national distance)의 조절효과를 분석하였다. 기존 연구는 오염피난처가설(PHH)과 포터가설(PH) 사이 에서 상반된 결과를 보여왔는데, 이는 국가 간 거리 요인을 간과한 데서 비롯된 것으로 보인다. 본 연구는 2001~2018년 한국의 해외직접투자 자료를 활용하여 제도적․문화적․지리적․경제적 거 리를 포함한 패널분석을 수행하였다. 분석 결과, 환경규제는 FDI에 긍정적인 영향을 미쳐 포터가 설을 지지하였다. 집계분석에서는 제도적 거리가 부정적 조절효과를 보였으며, 산업별 분석에서는 이질적 패턴이 확인되었다. 제조업에서는 문화적 거리가 환경규제의 긍정적 효과를 강화하였고, 서 비스업에서는 지리적․경제적 거리가 유의한 조절효과를 나타냈다. 이러한 결과는 ESG 시대의 맥 락에서 환경규제–FDI 관계를 보다 정교하게 이해할 수 있는 이론적 기여를 제공한다. 실무적으로 는 기업이 환경규제를 혁신의 기회로 인식하고 산업별 거리 요인을 고려한 전략을 수립해야 함을 시사하며, 정책적으로는 제조업에는 문화적 학습과 기술이전 촉진, 서비스업에는 제도적 장벽 완화 와 규제 예측 가능성 제고가 필요함을 보여준다.

This study investigated the legibility distance characteristics of variable speed limit signs and variable message signs under foggy conditions according to different luminance levels. In South Korea, the current installation standards for these signs are based on normal weather conditions, and empirical analyses of their visibility under adverse weather conditions remain limited. To address this issue, a controlled large-scale experiment was conducted at the Yeoncheon SOC Test Center, where artificial fog was generated in a tunnel environment. Seventeen elderly participants (average age: 70 years) participated in the experiment. They walked toward a sign to identify the distance at which it became legible. The experiment varied the fog visibility levels (50–80 m, 30–50 m, and 10–30 m) and display luminance (six levels). The results showed that as the fog density increased (that is, visibility decreased), the average legibility distance decreased. Conversely, higher luminance levels consistently improved legibility distance under foggy conditions. Under normal weather conditions, changes in luminance had a minimal impact on legibility. Compared with the minimum legibility distances calculated based on the design speed, many cases under foggy conditions failed to meet these thresholds, particularly at lower luminance levels. These findings indicate that the current luminance standards may not adequately ensure sign legibility under adverse weather conditions, underscoring the need for updated luminance guidelines that reflect environmental conditions. The results of this study provided quantitative data to support policy revisions and technical advancements aimed at improving road safety.