• Journal of the Korean Wood Science and Technology
• /
• v.33 no.5 s.133
• /
• pp.66-75
• /
• 2005

Soybean-based adhesives have recently been reconsidered as alternatives to petroleum-based adhesives due to the uncertainty of availability of petrochemical products and the increased demand for wood adhesives. This study was conducted to investigate the adhesive properties of alkaline phenolic soy (APS) resin for hybrid poplar flakeboard. The APS resin was formulated by crosslinking an alkaline soy flour hydrolyzate with lab-prepared PF resin in the soy hydrolyzate to PF resin weight ratios of 70/30, 60/40, and 50/50. The APS resins were used to fabricate homogeneous hybrid poplar flakeboards with different resin solid levels (5%, 7%, and 9%), press temperatures (175 and $200^{\circ}C$), and press times of 8 and 10 minutes. The IB, wet MOR, and dimensional stability properties of board improved with increasing press time, press temperature, and PF level in APS resins. Increasing press time can be used to offset poor IB strength associated with a 9% resin solid level and the excessive moisture content in the mat. The following conditions were concluded to meet the requirements of the CSA standard for exterior-grade flakeboard: a 50% PF level, a 5% resin content, a $200^{\circ}C$ press temperature, and an 8 minute press time.

• Spatial Information Research
• /
• v.14 no.1 s.36
• /
• pp.115-128
• /
• 2006

The aim of the study is to select and verify for development of groundwater resources using Geographic Information System(GIS). The water balance, land cover, forest, soil, elevation, slope, hydrogeology and lineament were analyzed. Using GIS, relationship between the data and groundwater yield data was analyzed and the groundwater resources potential map was made for selecting suitable area for groundwater development. Then groundwater resource potential map was verified using groundwater yield data. The verified result showed the good agreement between the potential map and groundwater yield data. The potential map can be used for groundwater management which is related to groundwater development.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.29 no.1
• /
• pp.11-21
• /
• 2001

This study investigates how motivations, preferences, and past experiences vary by each hikers trail choice at the Mt.Keyryong National Park. The purpose of this study is to find out the factors influencing behavioral choice in the recreation areas, and establish the fundamental theory for the efficient management of the resource and visitors. For this study, we have collected 472 respondents by on-site self-administrated questionnaire from the hikers in the park. The collected data were analyzed by the descriptive statistics and the discriminant analysis. The motivations variable of hiking participation on mountain trail were categorized three types; close-nature, escapism, and physical improvement. The preferences for trail environment were classified as four categories by factor analysis; preference for nature, safety, use density, and facilities. In descriptive statistics, the study showed that the experienced hikers prefer natural trials and hikers who have preference for close-nature select longer and deeper forest trails. The results of discriminant analysis indicate that the level of past experience is the most affectable in classification of trail choice. Such variables as motivation for close-nature and preference for nature were also appeared as affecting factors on classification of trail choice. Two discriminant functions were available, and 90.5 percent of analysis sample were correctly classified. In the validity analysis, 89 percent of holdout sample were correctly classified. These hit ratios ensures an accuracy by Press Q test. The result of this study is to be useful knowledge of the choice of detailed use environments in the same recreation areas.

• Plant Resources
• /
• v.7 no.1
• /
• pp.77-86
• /
• 2004

The reduced ratio of red:far-red (R:FR) light acts as a measure of the proximity of competitors and plants can detect the potentially competing neighbor plants by perceiving reflected R:FR signals and initiate the response of “shade avoidance” before actual shading occurs. The phytochrome system is responsible for monitoring the changes in the R:FR and initiating the shade avoidance response. The response to low R:FR ratio was studied in a white aspen Populus alba clone ‘Bolleana’ using two filter systems: a clear plastic filter system that allows a R:FR ratio less than 1.0 to pass from adjacent border plant reflection; and a special commercial plastic that blocks FR light and creates a R:FR ratio above 3.0. The reduced R:FR signals enhanced the stem elongation in response to competition at the expense of relative stem diameter growth. Trees grown inside clear chambers were 27 ％ taller than trees grown inside the FR-blocking filter chambers. Stem taper of clear chamber trees was 16％ less than the FR-blocking filter trees. Low R:FR also induced 22％ more stem dry weight and 13％ greater petiole length per leaf compared to the FR-blocking filter trees. There were no statistically significant differences in leaf area, leaf number increment, and total dry weight between the two light filter treatments.

• Journal of Ecology and Environment
• /
• v.47 no.4
• /
• pp.193-199
• /
• 2023

Background: The least weasel (Mustela nivalis) holds the distinction of being the world's smallest carnivorous animal, yet its presence in South Korea has remained poorly understood. To address this knowledge gap, this study investigates the habitat preferences and distribution of the least weasel in South Korea. Results: Our study compiled presence data from various sources, including citizen reports, national surveys, and expert observations. The results confirmed the nationwide presence of the least weasel in mainland South Korea, with notable concentration regions such as Gangwon province. Among the various habitats, forest edges and forests emerged as the predominant choice, with over half of the documented locations situated within these environments, particularly in broadleaf forests. Additionally, the data reveal a year-round presence of the least weasel, with recorded cases occurring at varying levels throughout the year. Conclusions: Our research advances the understanding of least weasels in South Korea. Despite the relatively modest dataset, our results provide as a valuable resource for future conservation initiatives, emphasizing the significance of forested landscapes. Additionally, it assists in identifying priority areas for protection and management efforts. To secure the future of the least weasel in South Korea and beyond, further research, including long-term monitoring and genetic studies, is imperative.

• Weed & Turfgrass Science
• /
• v.6 no.2
• /
• pp.136-150
• /
• 2017

Zoysiagrass mite, Aceria zoysiae is one of the main turfgrass pests causing significant damage on zoysiagrass. In this study we investigated damage by zoysiagrass mite for the selection of zoysiagrass mite-resistance turfgrass individual in natural collected turfgrass isolates transplanted in genetic resources conservation area. In the results of investigation of 295 turfgrass isolates collected from Korea, damage level was different depending on turfgrass species and individuals. Zoysia japonica was highly damaged representing 97.6%, followed by hybrid zoysia and Z. sinica with damage percentages of 87.7% and 81.1% respectively. Additionally, 2 individuals of Z. macrostachya were also damaged by zoysiagrass mite. However several individuals were not damaged by zoysiagrass mite in green house and field. Damage by zoysiagrass mite was occurred from May and peak at after July in field. The study highlighted some important resistant turfgrass individuals which can be used in the management of zoysiagrass mite.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.45 no.4
• /
• pp.92-103
• /
• 2017

As a professional occupation, landscape education focuses on fostering professional human resources and is one of the major axes of the landscape industry. In this study, a survey of landscape students on their learning and pedagogics was conducted with the aim to present basic information for the improvement of teaching on landscape construction. A total of 348 people answered 14 questions in the category of the impression of landscape construction classes included in the questionnaire. The results showed that the students found landscape construction classes academically important and recognized the necessity for completing these classes, but they were not satisfied with the learning environments and pedagogics used in these classes. They found what they learned not readily applicable to actual practice and saw these classes as part of their preparations for the landscape engineer qualification test. Their demands in relation to the classes included field practice-oriented teaching and participation in various programs for field practice, which highlights the necessity for human resource management-oriented classes that cover planning, design, construction, and management. Challenges in relation to field practice included the provision of environment, for example offering a variety of opportunities and improving treatment in practice. This study has significance in that it analyzed the views of students and discussed directions for future improvement since there is a lack of studies and discussions about education in the field of landscape construction. This study also has a limitation that only four-year universities were included in the study. Comprehensive studies including investigating junior college and graduate school curricula and case studies of landscape construction curricula overseas are needed in the future.

• Korean Journal of Remote Sensing
• /
• v.39 no.6_1
• /
• pp.1341-1352
• /
• 2023

The normalized difference vegetation index (NDVI) derived from satellite images is a crucial tool to monitor forests and agriculture for broad areas because the periodic acquisition of the data is ensured. However, optical sensor-based vegetation indices(VI) are not accessible in some areas covered by clouds. This paper presented a synthetic aperture radar (SAR) based approach to retrieval of the optical sensor-based NDVI using machine learning. SAR system can observe the land surface day and night in all weather conditions. Radar vegetation indices (RVI) from the Sentinel-1 vertical-vertical (VV) and vertical-horizontal (VH) polarizations, surface elevation, and air temperature are used as the input features for an automated machine learning (AutoML) model to conduct the gap-filling of the Sentinel-2 NDVI. The mean bias error (MAE) was 7.214E-05, and the correlation coefficient (CC) was 0.878, demonstrating the feasibility of the proposed method. This approach can be applied to gap-free nationwide NDVI construction using Sentinel-1 and Sentinel-2 images for environmental monitoring and resource management.

• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.304-311
• /
• 2022

Construction inspection is a crucial stage that ensures that all contractual requirements of a construction project are verified. The construction inspection capabilities among state highway agencies have been greatly affected due to budget reduction. As a result, efficient inspection practices such as risk-based inspection are required to optimize the use of limited resources without compromising inspection quality. Automated prioritization of textual requirements according to their criticality would be extremely helpful since contractual requirements are typically presented in an unstructured natural language in voluminous text documents. The current study introduces a novel model for predicting the risk level of requirements using machine learning (ML) algorithms. The ML algorithms tested in this study included naïve Bayes, support vector machines, logistic regression, and random forest. The training data includes sequences of requirement texts which were labeled with risk levels (such as very low, low, medium, high, very high) using the fuzzy logic systems. The fuzzy model treats the three risk factors (severity, probability, detectability) as fuzzy input variables, and implements the fuzzy inference rules to determine the labels of requirements. The performance of the model was examined on labeled dataset created by fuzzy inference rules and three different membership functions. The developed requirement risk prediction model yielded a precision, recall, and f-score of 78.18%, 77.75%, and 75.82%, respectively. The proposed model is expected to provide construction inspectors with a means for the automated prioritization of voluminous requirements by their importance, thus help to maximize the effectiveness of inspection activities under resource constraints.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.13 no.2
• /
• pp.69-78
• /
• 2011

Rice is one of the world's staple foods. Paddy rice fields have unique biophysical characteristics that the rice is grown on flooded soils unlike other crops. Information on the spatial distribution of paddy fields and the timing of irrigation are of importance to determine hydrological balance and efficiency of water resource management. In this paper, we detected the timing of irrigation and spatial distribution of paddy fields using the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the NASA EOS Aqua satellite. The timing of irrigation was detected by the combined use of MODIS-based vegetation index and Land Surface Water Index (LSWI). The detected timing of irrigation showed good agreement with field observations from two flux sites in Korea and Japan. Based on the irrigation detection, a land cover map of paddy fields was generated with subsidiary information on seasonal patterns of MODIS enhanced vegetation index (EVI). When the MODISbased paddy field map was compared with a land cover map from the Ministry of Environment, Korea, it overestimated the regions with large paddies but underestimated those with small and fragmented paddies. Potential reasons for such spatial discrepancies may be attributed to coarse pixel resolution (500 m) of MODIS images, uncertainty in parameterization of threshold values for discarding forest and water pixels, and the application of LSWI threshold value developed for paddy fields in China. Nevertheless, this study showed that an improved utilization of seasonal patterns of MODIS vegetation and water-related indices could be applied in water resource management and enhanced estimation of evapotranspiration from paddy fields.