• Smart Structures and Systems
• /
• v.30 no.5
• /
• pp.521-535
• /
• 2022

Efficient management of deteriorating civil infrastructure is one of the most important research topics in many developed countries. In particular, the remote displacement measurement of bridges using linear variable differential transformers, global positioning systems, laser Doppler vibrometers, and computer vision technologies has been attempted extensively. This paper proposes a remote displacement measurement system using closed-circuit televisions (CCTVs) and a computer-vision-based method for in-situ bridge bearings having relatively large displacement due to temperature change in long term. The hardware of the system is composed of a reference target for displacement measurement, a CCTV to capture target images, a gateway to transmit images via a mobile network, and a central server to store and process transmitted images. The usage of CCTV capable of night vision capture and wireless data communication enable long-term 24-hour monitoring on wide range of bridge area. The computer vision algorithm to estimate displacement from the images involves image preprocessing for enhancing the circular features of the target, circular Hough transformation for detecting circles on the target in the whole field-of-view (FOV), and homography transformation for converting the movement of the target in the images into an actual expansion displacement. The simple target design and robust circle detection algorithm help to measure displacement using target images where the targets are far apart from each other. The proposed system is installed at the Tancheon Overpass located in Seoul, and field experiments are performed to evaluate the accuracy of circle detection and displacement measurements. The circle detection accuracy is evaluated using 28,542 images captured from 71 CCTVs installed at the testbed, and only 48 images (0.168%) fail to detect the circles on the target because of subpar imaging conditions. The accuracy of displacement measurement is evaluated using images captured for 17 days from three CCTVs; the average and root-mean-square errors are 0.10 and 0.131 mm, respectively, compared with a similar displacement measurement. The long-term operation of the system, as evaluated using 8-month data, shows high accuracy and stability of the proposed system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.37 no.1
• /
• pp.36-42
• /
• 2024

Roll-to-roll processing holds an integral position within the manufacturing landscape, and its significance reverberates across numerous industries. This versatile technology platform encompasses a diverse array of process methods and accommodates a wide spectrum of material categories, making it a cornerstone of modern production. Within this expansive domain, two commonly employed coating techniques, namely the slot die and gravure coating methods, have earned their prominence for their precision and efficiency in delivering flawless coatings. Additionally, the realm of drying processes relies heavily on thermal drying, infrared (IR) drying, and ultraviolet (UV) drying methods to expedite the transformation of materials from their liquid or semi-liquid states to solid, ready-to-use products. The undeniable importance of roll-to-roll processing lies in its ability to streamline manufacturing processes, reduce costs, and enhance product quality. This article embarks on a comprehensive journey to fathom the depth of this importance by delving into the intricacies of these common roll-to-roll process methods. Through rigorous research and meticulous data collection, we aim to shed light on the pivotal role these techniques play in shaping various industries and advancing the world of manufacturing. By understanding their significance, we can harness the full potential of roll-to-roll processing and pave the way for innovation and excellence in production.

• Journal of Korean Society of Forest Science
• /
• v.112 no.4
• /
• pp.530-543
• /
• 2023

Societal value of the benefits forests provide has grown significantly, given their pivotal role in mitigating climate change and fostering the shift toward a carbon-neutral society. Due to the economic and public value of forests, which extends far beyond landowners and foresters, the forestry sector mutually interacts with society as a whole. Thus, understanding public perceptions and preferences concerning forests and forest policies from the societal viewpoint is vital for shaping future forest policy decisions. This research delved into evolving perceptions over the past 32 years, using a time-series analysis of data gathered from the 'Public awareness survey on forests'. This survey, conducted seven times between 1991 and 2023 by opinion poll agents, provides insights into changing sentiments. The findings reveal a notable increase in public satisfaction with overall forest policies. Specifically, positive sentiments were observed regarding forest rehabilitation, forest trails, education initiatives, and the establishment and functioning of forest recreation facilities. Conversely, the study highlights areas where public satisfaction remained relatively low, notably in matters concerning the use and conversion of mountainous regions, forest disaster prevention, and international forest cooperation. Additionally, the respondents emphasized the need for heightened attention to forest management, the development of forest roads, and increased efforts in overseas afforestation compared to current initiatives.

• Journal of Korean Society of Forest Science
• /
• v.112 no.4
• /
• pp.405-416
• /
• 2023

In this study, the sustainability of Abies nephrolepis in the presence of Tripterygium regelii was analyzed. To accomplish this, a field survey of140 stands was conducted. Based on the presence or absence of T. regelii, as well as the layer in which it was present (where appropriate), the type of T. regelii presence wasclassified as follows: TP type, indicating the presence of T. regelii in the tree and sub-tree layers; SP type, indicating its presence in the shrub layer; and A type, indicatingits absence from all layers. The indicator species analysis revealed T. regelii to be an indicator species of the TP type and SP type. The MRPP test was used to examine the differences among the types. Moreover, the seedling and DBH class analysis indicated there to be a difficulty in terms of the status competition, as the number of young trees generated by A. nephrolepis was the lowest in the TP type. The findings of this study enhanced our understanding of the vegetation structure of A. nephrolepis, thereby contributing to efforts concerningits conservation and management.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.19 no.2
• /
• pp.1-11
• /
• 2024

In the midst of the current turbulent global economy, traditional investment metrics are undergoing a metamorphosis, signaling the onset of what's often referred to as an "Investment cold season". Early-stage startups, despite their boundless potential, grapple with immediate revenue constraints, intensifying their pursuit of critical investments. While financial indicators once took center stage in investment evaluations, a notable paradigm shift is underway. Organizational culture, once relegated to the sidelines, has now emerged as a linchpin in forecasting a startup's resilience and enduring trajectory. Our comprehensive research, integrating insights from CVF and OCAI, unveils the intricate relationship between organizational culture and its magnetic appeal to investors. The results indicate that startups with a pronounced external focus, expertly balanced with flexibility and stability, hold particular allure for investment consideration. Furthermore, the study underscores the pivotal role of adhocracy and market-driven mindsets in shaping investment desirability. A significant observation emerges from the study: startups, whether they secured investment or failed to do so, consistently display strong clan culture, highlighting the widespread importance of nurturing a positive employee environment. Leadership deeply anchored in market culture, combined with an unwavering commitment to innovation and harmonious organizational practices, emerges as a potent recipe for attracting investor attention. Our model, with an impressive 88.3% predictive accuracy, serves as a guiding light for startups and astute investors, illuminating the intricate interplay of culture and investment success in today's economic landscape.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.34 no.4
• /
• pp.763-780
• /
• 2024

As the domestic and international landscape undergoes rapid changes, the importance of implementing security measures in response to the growing threats that businesses face is increasing. In this context, the need for Security by Design (SbD), integrating security from the early design stages, is becoming more pronounced, with threat modeling recognized as a fundamental tool of SbD. Particularly, to save costs and time by detecting and resolving security issues early, the application of the Shift Left strategy requires the involvement of personnel with limited security expertise, such as software developers, in threat modeling. Although various automated threat modeling tools have been released, their lack of user-friendliness for personnel lacking security expertise poses challenges in conducting threat modeling effectively. To address this, we conducted an analysis of research related to threat modeling tools and derived usability evaluation criteria based on the GQM(Goal-Question-Metric) approach. An expert survey was conducted to validate both the validity and objectivity of the derived criteria. We performed usability evaluations of three threat modeling tools (MS TMT, SPARTA, PyTM), and the evaluation results led to the conclusion that MS TMT exhibited superior usability compared to other tools. This study aims to contribute to the creation of an environment where personnel with limited security expertise can effectively conduct threat modeling by proposing usability evaluation criteria.

• Journal of Bio-Environment Control
• /
• v.17 no.3
• /
• pp.231-237
• /
• 2008

Objective of this research was to investigate the effect of calcium concentrations in the fertilizer solution on growth and development of Ca deficiency in 'Maehyang' strawberry (Fragaria $\times$ ananassa Duch.). The margins of the youngest leaves were scorched and they developed a cupped shape as they were expanded in Ca deficient plants. The vein area of the youngest leaves became brown when the deficiency became severe. The quadratic responses were observed in dry weight production to elevated Ca concentrations in fertilizer solutions with the highest growth in 4.5 mM treatment. The regression equation was y=2.4026+1.0209x-$0.098x^2$ $(R^2=0.3546^{***})$. However, tissue Ca contents increased lineally as the Ca concentrations in fertilizer solutions were elevated (y=1.2108+0.1333x, $R^2=0.9189^{***}$). In changes of the fresh weight and Ca concentrations in petiole sap, fresh weight production showed quadratic responses to elevated Ca concentrations in fertilizer solution, but Ca concentration increased lineally. The equations in changes of fresh weight and Ca concentrations were y=9.273+4.882x-$0.4245x^2$ $(R^2=0.4935^{***})$ and y=52.311+3.2917x $(R^2=0.6918^{***})$, respectively. When the concentration of calcium at which plant growth was retarded by 10% is regarded as critical concentration level, the calcium contents based on dry weight of above ground plant tissue and in petiole sap should be in the range between 1.6 to 2.25% and 63 to $79mg{\cdot}kg^{-1}$, respectively.

• Journal of the Korean Geographical Society
• /
• v.50 no.3
• /
• pp.255-276
• /
• 2015

This paper presents a multi-agent system model of land-use and cover changes, which is developed and applied to the Gariwang-san and its vicinity, located in Pyeongchang and Jeongseon-gun, Gangwon province, Korea. The Land Use Dynamics Simulator (LUDAS) framework of this study is well suited for representing the spatial heterogeneity and dynamic interactions between human and natural environment, and capturing the impacts of forest-opening policy interventions to future socio-economic and natural environment changes. The model consists of four components: (1) a system of human population, (2) a system of landscape environment, (3) decision-making procedures integrating human(or household), environmental and policy information into forest land-use decisions, and (4) a set of policy scenarios that are related to the forest-opening. The results of model simulation by different combination of various forest management scenarios are assessed by the levels of household income, ecosystem service value and income inequality in the study region. As a result, the optimal scenario of forest-opening policies in the study region is to open the forest to local residential community for the purpose of recreation, considering the distinctive topographical feature. The model developed in this research is expected to contribute to a decision support system for sustainable forest management and various land-use policies in Korea.

• Korean journal of applied entomology
• /
• v.57 no.3
• /
• pp.127-135
• /
• 2018

Climate change can affect variables related to the life cycle of insects, including growth, development, survival, reproduction and distribution. As it encourages alien insects to rapidly spread and settle, climate change is regarded as one of the direct causes of decreased biodiversity because it disturbed ecosystems and reduces the population of native species. Hypera postica caused a great deal of damage in the southern provinces of Korea after it was first identified on Jeju lsland in the 1990s. In recent years, the number of individuals moving to estivation sites has concerned scientists due to the crop damage and national proliferation. In this study, we examine how climate change could affect inhabitation of H. postica. The MaxEnt model was applied to estimate potential distributions of H. postica using future climate change scenarios, namely, representative concentration pathway (RCP) 4.5 and RCP 8.5. As variables of the model, this study used six bio-climates (bio3, bio6, bio10, bio12, bio14, and bio16) in consideration of the ecological characteristics of 66 areas where inhabitation of H. postica was confirmed from 2015 to 2017, and in consideration of the interrelation between prediction variables. The fitness of the model was measured at a considered potentially useful level of 0.765 on average, and the warmest quarter has a high contribution rate of 60-70%. Prediction models (RCP 4.5 and RCP 8.5) results for the year 2050 and 2070 indicated that H. postica habitats are projected to expand across the Korean peninsula due to increasing temperatures.

• Journal of Korean Society of Forest Science
• /
• v.104 no.3
• /
• pp.390-396
• /
• 2015

This study was carried out in order to closely examine quality index by shading level of 2-year-old (1-1 seedling) container seedling of Daphniphyllum macropodum which is known as the species of having shade tolerance that is evergreen broad leaved tree in the warm temperate region. The shading treatment was regulated with the shading level of full sunlight, and 35%, 55%, 75%, 95% of full sunlight. As a result of surveying growth according to the shading level, both height and root collar diameter were surveyed to be the highest with 45.1 cm and 8.22 mm, respectively, under 75% of shading. The next was surveyed to be 43.2 cm & 8.05 mm and 42.5 cm & 7.98 mm, respectively, in order of 35% and 55% in shading. Leaf, shoot, root, and whole dry mass production were the highest under 75% of shading. The next was higher in leaf, stem, and whole dry mass production under 55% of shading. A root was higher under 35% of shading in the next. H/D ratio was the range of 5.29~5.35 under the 35~75% shading that showed the relatively high height and root collar diameter. T/R ratio was the lowest with 1.17 under 35% of shading. It was 0.41 under 95% of shading as for LWR, 0.24 under 75%-95% of shading as for SWR, and 0.46 under full sun and 35% shading as for RWR. QI was the highest with 3.74 under 75% of shading. As a result of surveying the whole experiment, it is concluded that the production of D. macropodum seedling is more effective under 75% shading