• Tunnel and Underground Space
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• v.32 no.6
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• pp.568-585
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• 2022

In the present study, we proposed a numerical method for simulating thermally induced fracture slip using a grain-based distinct element model (GBDEM). As a part of DECOVALEX-2023, the thermo-mechanical loading test on a saw-cut rock fracture conducted at the Korea Institute of Civil Engineering and Building Technology was simulated. In the numerical model, the rock sample including a saw-cut fracture was represented as a group of random Voronoi polyhedra. Then, the coupled thermo-mechanical behavior of grains and their interfaces was calculated using 3DEC. The key concerns focused on the temperature evolution, thermally induced principal stress increment, and fracture normal and shear displacements under thermo-mechanical loading. The comparisons between laboratory experimental results and the numerical results revealed that the numerical model reasonably captured the heat transfer and heat loss characteristics of the rock specimen, the horizontal stress increment due to constrained displacement, and the progressive shear failure of the fracture. However, the onset of the fracture slip and the magnitudes of stress increment and fracture displacement showed discrepancies between the numerical and experimental results. We expect the numerical model to be enhanced by continuing collaboration and interaction with other research teams of DECOVALEX-2023 Task G and validated in further study.

• Journal of Practical Engineering Education
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• v.14 no.2
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• pp.405-411
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• 2022

In this study, K-Digital Training program, which is a representative government project of vocational training for new digital technologies in response to the 4th industrial revolution, is analyzed and an improvement model is suggested. The K-Digital training project is rapidly expanding, with the number of training operators increasing by 7.1 times and training course programs by 8.5 times within three years of implementation, but there is a severe problem in that education and training programs are concentrated in the metropolitan. To solve this problem, a shared training model is proposed. This model is a plan to maximize the use of local human and material resources, to respond to new digital technologies through systematic composition and operation, and to enhance the stability and reliability of education and training. In each region, a sharing and cooperation model in the form of a consortium is established that jointly utilizes resources scattered by various training institutions such as instructors, training contents, and training infrastructure related to digital new technology. In addition, a training certification evaluation system is introduced to increase the credibility of the rapidly developing digital new technology training.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.1
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• pp.55-61
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• 2023

This study aims to develop CLSM fill material for emergency restoration using landfill coal ash. As a result of examining physical properties such as particle size distribution and fines content of landfill coal ash, bottom ash, fly ash, and general soil were mixed, and SP was found to have a density of 2.03 and a residual particle pass rate of 7.8 %. CLSM materials that secure fluidity in unit quantities without using chemical admixtures such as glidants and water reducing agents have a high risk of material separation due to bleeding. As a result of this experiment, it was found that the bleeding ratio did not satisfy the standard in the case of the specimen with a large amount of fly ash and a lot of addition of mixing water. As a result of the compressive strength test, the strength development of 0.5 MPa or more for 4 hours was found to be satisfactory for the specimens using hemihydrate gypsum with a unit binder amount of 200 or more, and the remaining gypsum showed poor strength development. Although it is judged that landfill coal ash can be used as a CLSM material, it is necessary to identify and apply the physical and chemical characteristics of coal ash buried in the ash treatment plant of each power generation company.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.258-264
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• 2023

The greenhouse gas (GHG) emission assessment of kenaf pellet, produced from locally generated kenaf residues in South Korea, has been studied based on the EU RED-II methodology for calculating GHG impact of biomass fuels. Based on the production pathway of kenaf residue pellet and emission coefficients from EU JRC report, the life cycle GHG emission of kenaf residue pellet is assessed as 3.0 gCO₂eq/MJ_pellet and the life cycle GHG emission of electricity generated from kenaf residue pellet is assessed as 11.9 gCO₂eq/MJ when electrical efficiency of final conversion is 25%. The potential GHG emission reduction of electricity produced from kenaf pellet is 90.3% compared to the domestic electricity emission factor 42.8 kgCO₂eq/MWh. Also, the electricity produced from kenaf pellet can reduce at least 59.6% of GHG emission compared to the electricity produced from imported wood pellets.

• Tunnel and Underground Space
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• v.33 no.3
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• pp.189-207
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• 2023

In the present study, the thermoshearing experiment on a rough rock fracture were modeled using a three-dimensional grain-based distinct element model (GBDEM). The experiment was conducted by the Korea Institute of Construction Technology to investigate the progressive shear failure of fracture under the influence of thermal stress in a critical stress state. The numerical model employs an assembly of multiple polyhedral grains and their interfaces to represent the rock sample, and calculates the coupled thermo-mechanical behavior of the grains (blocks) and the interfaces (contacts) using 3DEC, a DEM code. The primary focus was on simulating the temperature evolution, generation of thermal stress, and shear and normal displacements of the fracture. Two fracture models, namely the mated fracture model and the unmated fracture model, were constructed based on the degree of surface matedness, and their respective behaviors were compared and analyzed. By leveraging the advantage of the DEM, the contact area between the fracture surfaces was continuously monitored during the simulation, enabling an examination of its influence on shear behavior. The numerical results demonstrated distinct differences depending on the degree of the surface matedness at the initial stage. In the mated fracture model, where the surfaces were in almost full contact, the characteristic stages of peak stress and residual stress commonly observed in shear behavior of natural rock joints were reasonably replicated, despite exhibiting discrepancies with the experimental results. The analysis of contact area variation over time confirmed that our numerical model effectively simulated the abrupt normal dilation and shear slip, stress softening phenomenon, and transition to the residual state that occur during the peak stress stage. The unmated fracture model, which closely resembled the experimental specimen, showed qualitative agreement with the experimental observations, including heat transfer characteristics, the progressive shear failure process induced by heating, and the increase in thermal stress. However, there were some mismatches between the numerical and experimental results regarding the onset of fracture slip and the magnitudes of fracture stress and displacement. This research was conducted as part of DECOVALEX-2023 Task G, and we expect the numerical model to be enhanced through continued collaboration with other research teams and validated in further studies.

• ANNALS OF ANIMAL RESOURCE SCIENCES
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• v.30 no.4
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• pp.165-171
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• 2019

The objective of this study was to investigate the effects of gender on meat quality traits and sensory characteristics of pork loin. A total of 90 pork carcasses (180 days old, 45 barrows and 45 gilts, each gender group was consisted of fifteen 1+, 1 and 2 carcass grades) were selected and loin cuts were excised to investigate meat quality, electronic tongue measures and sensory panel test. There were significant differences in drip loss (1.66% vs 1.21%), released water (12.19% vs 10.68%) and cooking loss (23.67% vs 21.04%) between loins from barrow and gilt (p<0.05). However, no significant differences in meat color (CIE L^* a^* b^*) and shear force were observed between gender groups (p>0.05). Umami and richness values of barrow were significantly higher than those of gilt, while barrow had significantly lower sourness value compared to gilt(p<0.05). On the sensory evaluation, barrow scored higher in flavor, juiciness and tenderness both, and as a result, barrow (5.51 points) also scored significantly higher than gilt (4.86 points). These results suggest that the umami intensity and sensory taste of barrow loin are superior to gilt loin due to its high water-holding capacity.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.2
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• pp.101-111
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• 2016

Startup has lot of limitation such as time and budget shortage, and few human resources, and may be under the very stressful condition. Naturally in these context, there is always conflict among the startup team members, but the impact of conflict on teamwork or team performance has not been empirically tested. This study examines the relationship among the conflict, teamwork and team performance in startup context. Different two types of conflict and four factors of teamwork for team performance are identified from a literature review and tested; task conflict and relationship conflict as antecedents, teamwork was composed of communication, collaboration, coordination and cohesion, leading to team performance. 142 data points were collected from startup representatives to test these hypotheses. PLS data analysis indicated that the task conflict positively effects on all teamwork factors, but relationship conflict has statistically significant effect on only two teamwork factors, collaboration and coordination in negative relationship. Teamwork factors effects on team performance except communication. Based on the results, we proposed practically several team management skills for startup managers, leaders and even members, and explained theoretical contributions.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.1
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• pp.38-45
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• 2017

Attacking of computer and network is increasing as information processing technology heavily depends on computer and network. To prevent the attack of system and network, host and network based intrusion detection system has developed. But previous rule based system has a lot of difficulties. For this reason demand for developing a intrusion detection system which detects and cope with the attack of system and network resource in real time. In this paper we develop a real time intrusion detection system which is combination of APEX and LS-SVM classifier. Proposed system is for nonlinear data and guarantees convergence. While real time processing system has its advantages, such as memory efficiency and allowing a new training data, it also has its disadvantages of inaccuracy compared to batch way. Therefore proposed real time intrusion detection system shows similar performance in accuracy compared to batch way intrusion detection system, it can be deployed on a commercial scale.

• 한국벤처창업학회:학술대회논문집
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• 2017.04a
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• pp.21-21
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• 2017

귀농귀촌 문화가 유행하고 농업의 미래 가치에 대한 인식이 변화되면서 농산업으로의 새로운 진출을 계획하는 인구가 늘고 있다. 우리의 농업은 자급자족경제로부터 상업경제로 발전되어 왔고, 글로벌 시장 개방 및 생산 기술의 지속적 발전으로 공급이 수요를 초과하며 가격이 점점하락하는 추세를 보이고 있다. 농업 현장의 여러 어려움에도 불구하고 농산업의 긍정적인 여건들도 형성되고 있다. 올바른 먹거리를 추구하는 식품 소비패턴의 변화, 환 생태 치유 자연에 대한 소비자의 관심고조, 스마트 팜과 같은 생산환경의 자동화, 지역 자원을 근거한 공동경영체 운영 등과 같은 현상이 두드러지게 나타나고 있다. 이러한 시점에 농산업분야에 새로이 진출하고자 하는 개인 또는 소규모 사업주체들은 자신의 사업에 대한 정체성을 이해하고, 효율적인 사업운영을 위한 차별화 전략을 확보할 필요가 있다. 본 연구는 개별 또는 소규모 조직의 농업인과 예비농업인들이 자신의 사업에 대한 정체성을 이해하고, 사업운영을 위한 전략 선택을 돕는 비즈니스모델 템플릿 개발을 목표로 하였다. 이를 위해 농업 전문가, 창업 전문가, 비즈니스모델 전문가 풀을 구성하여 농산업 특성을 이해하고 최근 농업 농촌에서 이슈가 되고 있는 농업비즈니스 트랜드를 분석하였다. 근거 자료 및 전문가 토론을 통해 농산업 비즈니스를 '시장가치 추구형', '사회적가치 추구형', '연대하는 시장가치 추구형', '연대하는 사회적가치 추구형'의 4가지 유형으로 구분하고, 각 유형별 사례기업을 조사하여 비즈니스모델을 분석하였다. 비즈니스모델은 비즈니스모델 젠 캔버스를 이용하여 표현하였다. 비즈니스모델 젠은 비즈니스 유형에 따라 일반 창업형, 협동조합형, 임팩트비즈니스형 등 차별화된 캔버스 모델을 제공하고 있으며, 고객중심의 비즈니스 관점을 보다 세밀히 제공하는 툴이다. 본 연구에서는 비즈니스모델 젠을 통해 4가지 유형의 농산업 비즈니스 모델을 분석하였다. 본 연구의 결과는 농산업에 진출하는 사업주체의 사업진행 방향 및 전략선택을 위한 교육 컨설팅 현장에서 널리 이용될 수 있을 것으로 판단된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8262-8273
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• 2015

Sources of innovation and a sustainable competitive advantage for market leading firms in a dynamic environment are major concerns for both firm managers and academic researchers. For this reason, the dynamic capability view (DCV), evolved from the resource-based view (RBV) is gaining popularity as a cornerstone for success of firms in a dynamic market. DCV proposes a number of new concepts and elements, but these are still under development. This study suggests a comprehensive constitution of dynamic capabilities by performing a systematic literature review of 59 conceptual research papers from 238 bodies of literature. For the integrative conceptual framework, the elements of the dynamic capabilities are segmented into organizational learning and strategic choices with sensing, seizing, and reconfiguring stages. In addition, our conceptual framework lays a foundation for further empirical studies, with investigating sources of competitive advantage of market leading firms.