• Tunnel and Underground Space
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• v.33 no.6
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• pp.534-546
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• 2023

If the disc cutter is excessively worn or damaged, it becomes incapable of rotating and efficiently cutting rockmass. Therefore, it is important to appropriately manage the replacement cycle of the disc cutter based on its degree of wear. In general, the replacement cycle is determined based on the results of manual inspection. However, the manual measurements has issues related to worker safety and may lead to inaccurate measurement results. For these reasons, some foreign countries are developing the real-time measurement system of disc cutter wear by using different sensors. The ultrasonic sensors, eddy current sensors, magnetic sensors, and others are utilized for measuring the wear amount of disc cutters. In this study, the applicability of eddy current sensors for real-time measurement of wear amount in TBM disc cutters was evaluated. The distance measurement accuracy of the eddy current sensor was assessed through laboratory tests. In particular, the accuracy of eddy-current sensor was evaluated in various environmental conditions within the cutterhead chamber. In addition, the measurement accuracy of the eddy current sensor was validated using a 17-inch disc cutter.

• Korean Journal of Culture and Social Issue
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• v.8 no.1
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• pp.41-59
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• 2002

The present study explored the major behavior patterns of drivers and the environmental settings having an effect on traffic accident using the data collected from drivers and traffic police. Drivers and traffic police read questionnaire which contain the passible causes of traffic accident and selected the major causes on the basis of their latest accidents. Unexperienced drivers were forced to answer the questionnaire by referring to their friends and neighborhoods. The results showed that the major causes of traffic accident were connected with the driver's factors. The most important cause of traffic accidents was inattention/incautiousness. The next were lack of competence, skill, and experience. One interesting fact was that drivers and traffic police attributed differently. Drivers pointed out the lack of ability coping with an emergency and the insufficient skill of defensive driving as causes of the traffic accident. On the other hand, traffic polices indicated the intentional violations such as the disregard for traffic rules, trespassing on the central line of the roadway, speed limit violation, and breaking into the vehicle's line. The implications for appling the this results to driver education institutions were discussed.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.5
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• pp.187-203
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• 2022

As the economic, social, and environmental problems of the local community reach a serious level, our society is realizing the need to foster young talents who discover opportunities in local issues through entrepreneurship education and create social values through creative challenges. However, entrepreneurship education programs are generally focused on commerciality, so customized education programs to solve regional problems are insufficient. Therefore, this study aimed to develop a community problem-solving entrepreneurship curriculum. In this study, a competency based curriculum model was applied to develop the curriculum, and regional problem-solving entrepreneurship competencies were derived through expert advice from a total of 10 people. In the process, the Delphi methodology was additionally used to reduce the possibility of errors in the competency model. As a result of the study, a total of 23 regional problem-solving entrepreneurship competencies were confirmed, and knowledge(K) - skill(S) - attitude(A) by competency consisted of 5, 9, and 9, respectively. By applying this to Dunham's problem-solving six-step model, modular learning support measures were developed in the order of phase 1(problem discovery), phase 2(problem analysis), phase 3(plan), phase 4(measure), and phase 5(evaluation). This study is meaningful in that it integrated theory and practice by developing specific entrepreneurship curriculum and learning support measures based on the theoretical model devised in social welfare. In addition, it has implications in that it developed a regional problem-solving entrepreneurship competency model based on expert advice and proposed a specific curriculum based on this.

• Journal of the Korean Regional Science Association
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• v.40 no.1
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• pp.37-51
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• 2024

To respond to local extinction, South Korea, under the leadership of the Ministry of the Interior and Safety, identified depopulated areas in 2021 and launched the Local Extinction Response Fund in 2022. However, due to its early stage of implementation, analyzing the characteristics and changes of policy response to local extinction at the central government level remains a challenge. In contrast, Japan, facing similar issues of local extinction as South Korea, has established a robust central government-led response system based on the Regional Revitalization Act and the Comprehensive Strategy and Basic Policy on Community-Population-Job Creation. Hence, this study examines Japan's policy responses to local extinction by analyzing the first and second periods of the Comprehensive Strategy and Basic Policy on Community-Population-Job Creation. For the analysis, topic modeling was employed to enhance text analysis efficiency and accuracy, complemented by expert interviews for validation. The results revealed that the first-period strategy's topics encompassed economy and society, start-up, local government, living condition, service, and industry. Meanwhile, the second-period strategy's topics included resource, the New Normal, woman, digital transformation, industry, region, public-private partnership, and population. The analysis highlights that the policy target, policy direction, and environmental change significantly influenced these policy shifts.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.1
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• pp.50-56
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• 2007

Impact of thermal discharge of nuclear power plant on marine environment is naturally reflected in biogeochemical changes of seawater. Until now, many investigation activities and reports of impact analysis of marine environment were occasionally inadequate to provide sufficient justification in resolving controversial conflict of interests related with thermal discharge of nuclear power plant. From the scrutinized examination of recent 17 reports published in Korea between 2002 and 2004, the most apparent issue was inadequacy of sampling design and absence of significance of many measured parameters. In many cases, lack of statistical interpretation of raw data incurred subjective or ambiguous assessment results, which failed in deducing mutual concurrence between the parties of interest. In overall all, the main reasons for impairing integrity of previous reports seem to be inconsistency of environmental investigation procedures between research institutions, inadequate sampling design at the discretion of institutions and lack of objectivity of impact assessment based on statistical interpretation. Therefore, the primary goal of this study is to (1) discuss the blown issues on previous routine practice of seawater quality assessment procedures, and to (2) provide improved investigation procedures and rational standard criteria strictly based on statistical analysis for the better seawater quality assessment, which could be supported by scientific community, public agency, investigation institution and the other parties of interest.

• Clean Technology
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• v.30 no.2
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• pp.105-112
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• 2024

Globally, the demand for electric vehicles has surged due to greenhouse gas regulations related to climate change, leading to an increase in the production of used batteries as a consequence of the battery life issue. This study aims to selectively leach and recover valuable metal lithium from the cathode material of spent LFP (LiFePO₄) batteries among lithium-ion batteries. Generally, the use of inorganic acids results in the emission of toxic gases or the generation of large quantities of wastewater, causing environmental issues. To address this, research is being conducted to leach lithium using organic acids and other leaching agents. In this study, selective leaching was performed using the organic acid methane sulfonic acid (MSA, CH₃SO₃H). Experiments were conducted to determine the optimal conditions for selectively leaching lithium by varying the MSA concentration, pulp density, and hydrogen peroxide dosage. The results of this study showed that lithium was leached at approximately 100%, while iron and phosphorus components were leached at about 1%, verifying the leaching efficiency and the leaching rates of the main components under different variables.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.2
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• pp.173-188
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• 2024

With the advancement of autonomous vehicle (AV) technology, autonomous driving on real roads has become feasible. However, there are challenges in achieving complete autonomy due to perceptual blind areas, which occur when the AV's sensory range or capabilities are limited or impaired by surrounding objects or environmental factors. This study aims to analyze AV accident patterns and safety issues of perceptual blind area that may occur in urban areas, with the goal of developing test scenarios for Level 4+ autonomous driving. It utilized AV accident data from the California Department of Motor Vehicles (DMV) to compare accident patterns and characteristics between AVs and conventional vehicles based on activation status of autonomous mode. It also categorized AV disengagement data to identify types and real-world cases of disengagements caused by perceptual blind areas. The analysis revealed that AVs exhibit different accident types due to their safe driving maneuvers, and three types of perceptual blind area scenarios were identified. The findings of this study serve as crucial foundational data for developing Level 4+ autonomous driving test scenarios, enabling the design of efficient strategies to mitigate perceptual blind areas in various scenarios. This, in turn, is expected to contribute to the effective evaluation and enhancement of AV driving safety on real roads.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.30 no.1
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• pp.1-14
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• 2024

As awareness of environmental issues continues to grow, there is an escalating demand for recycling and repurposing byproducts of agricultural and food production processes and their conversion to high-value products. Coffee is the most widely consumed beverage globally; during coffee beverage processing and consumption, byproducts such as coffee silverskin (CS), spent coffee grounds (SCGs), and oil are generated. Despite containing beneficial materials such as cellulose, hemicellulose, lignin, lipids, and bioactive substances, these byproducts are typically discarded in landfills or incinerated. The utilization of CS, SCGs, and oil in the development of packaging materials holds significant potentials toward the realization of a sustainable society. To this end, considerable research efforts have been dedicated to the development of high-value materials derived from coffee byproducts, including functional fillers, polymer composites, and biodegradable polymers. Notably, CS and SCGs have been employed as functional fillers in polymer composites. Additionally, lipids extracted from SCGs have been used as plasticizers for polymers and cultured with microorganisms to produce biodegradable polymers. This review focuses on the research and development of polymer/CS and polymer/SCG composites as well as cellulose extraction and utilization from CS and SCGs and its applications, oil extraction from SCGs, and cultivation with microorganisms using extracted oil for polyhydroxyalkanoates(PHA) production.

• Smart Media Journal
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• v.13 no.6
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• pp.80-89
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• 2024

This study aims not only to address environmental issues caused by indiscriminate fashion consumption, specifically in the context of Fast Fashion but also to find an alternative and a sustainable solution that is 'Upcycling' using the 3D clothing simulation program Z-weave. Upcycling products have limitations in that it is difficult to produce samples since finished products must be produced directly with limited materials and resources like waste clothes. To overcome these limitations, a 3D clothing simulation program is introduced to effectively utilize the limited resources of waste clothing. The purpose of this study is to confirm the similarity between a virtual fabric created through Z-weave and a real fabric, through this, to evaluate the possibility of application in the actual fashion industry. As a research method, surveys and interviews were conducted with related majors on virtual clothing created as similar as possible to actual clothing by adjusting the physical properties within the Z-weave program. This study attempted to describe the impact of digital technology on the fashion industry and how 3D clothing simulation programs can be used in sustainable fashion production.

• Journal of Ecology and Environment
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• v.47 no.4
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• pp.228-240
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• 2023

Growing complexity in ecosystem structure and functions, under impacts of climate and land-use changes, requires interdisciplinary understandings of processes and the whole-system, and accurate estimates of the changing functions. In the last three decades, observation networks for biodiversity, ecosystems, and ecosystem functions under climate change, have been developed by interested scientists, research institutions and universities. In this paper we will review (1) the development and on-going activities of those observation networks, (2) some outcomes from forest carbon cycle studies at our super-site "Takayama site" in Japan, and (3) a few ideas how we connect in-situ and satellite observations as well as fill observation gaps in the Asia-Oceania region. There have been many intensive research and networking efforts to promote investigations for ecosystem change and functions (e.g., Long-Term Ecological Research Network), measurements of greenhouse gas, heat, and water fluxes (flux network), and biodiversity from genetic to ecosystem level (Biodiversity Observation Network). Combining those in-situ field research data with modeling analysis and satellite remote sensing allows the research communities to up-scale spatially from local to global, and temporally from the past to future. These observation networks oftern use different methodologies and target different scientific disciplines. However growing needs for comprehensive observations to understand the response of biodiversity and ecosystem functions to climate and societal changes at local, national, regional, and global scales are providing opportunities and expectations to network these networks. Among the challenges to produce and share integrated knowledge on climate, ecosystem functions and biodiversity, filling scale-gaps in space and time among the phenomena is crucial. To showcase such efforts, interdisciplinary research at 'Takayama super-site' was reviewed by focusing on studies on forest carbon cycle and phenology. A key approach to respond to multidisciplinary questions is to integrate in-situ field research, ecosystem modeling, and satellite remote sensing by developing cross-scale methodologies at long-term observation field sites called "super-sites". The research approach at 'Takayama site' in Japan showcases this response to the needs of multidisciplinary questions and further development of terrestrial ecosystem research to address environmental change issues from local to national, regional and global scales.