• International journal of advanced smart convergence
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• 제13권2호
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• pp.276-283
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• 2024

Currently, the overall tendency for green and sustainable economic development is creating a circular economy. In actuality, agricultural output is currently benefiting greatly from the growth of the circular economy. The creation of a circular economy helps address resource scarcity, save the environment, combat climate change, and increase economic efficiency. Vietnam's economy can grow quickly and sustainably by shifting to a circular economy production model. Comparing prior growth techniques to the digital age and implementing circular economic development connected with high technology will be a fantastic opportunity to boost growth efficiency. In actuality, Vietnam currently has a large number of agricultural circular economy models. These are models: Creating and using gas from waste and wastewater in livestock and farming; model combining cultivation, livestock, and aquaculture; agro-forestry model; garden-forest model; Circular model using agricultural by-products as a catalyst or creating other valuable products; model of moderation, linked to reducing the use of growth hormones, veterinary medications, pesticides, and artificial fertilizers in agriculture and animal husbandry. Unfortunately, there have been few studies and applications of the aforementioned models, which has made it difficult to build the agricultural sector sustainably. In this paper, we outline the current situation and propose solutions to develop a circular economy model in agriculture in Vietnam for sustainable development.

• 수산해양기술연구
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• 제57권3호
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• pp.214-227
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• 2021

The distribution of tidal current and tidal induced residual current, topographical eddies and tidal residual circulation in the waters surrounding the Geumo Island-An Island channel were identified through numerical model experiments and vorticity balance analysis. Tidal current flows southwest at flood and northeast at ebb along the channel. The maximum flow velocity was about 100-150 cm/s in neap and spring tide. During the flood current in the neap tide, clockwise small eddies were formed in the waters west of Sobu Island and southwest of Daebu Island, and a more grown eddy was formed in the southern waters of Geumo Island in the spring tide. A small eddy that existed in the western waters of Chosam Island during the ebb in neap tide appeared to be a more grown topographical eddy in the northeastern waters of Chosam Island in spring tide. Tidal ellipses were generally reciprocating and were almost straight in the channel. These topographical eddies are made of vorticity caused by coastal friction when tidal flow passes through the channel. They gradually grow in size as they are transported and accumulated at the end of the channel. When the current becomes stronger, the topographic eddies move, settle, spread to the outer sea and grow as a counterclockwise or clockwise tidal residual circulation depending on the surrounding terrain. In the waters surrounding the channel, there were counterclockwise small tidal residual circulations in the central part of the channel, clockwise from the northeast end of the channel to northwest inner bay of An Island, and clockwise and counterclockwise between Daebu Island and An Island. The circulation flow rate was up to 20-30 cm/s. In the future, it is necessary to conduct an experimental study to understand the growth process of the tidal residual circulation in more detail due to the convergence and divergence of seawater around the channel.

• 한국항해항만학회지
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• 제46권5호
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• pp.449-457
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• 2022

The Port of Busan is currently ranked as the seventh largest container port worldwide in terms of cargo throughput. However, port competition in the Far-East region is fierce. The growth rate of container throughput handled by the port of Busan has recently slowed down. In this study, we analyzed how economic conditions and multiple external shocks could influence cargo throughput and identified potential implications for port business. The aim of this study was to build a model to accurately forecast port throughput using the ARIMA model, which could incorporate external socio-economic shocks, and the VEC model considering causal variables having long-term effects on transshipment cargo. Findings of this study suggest that there are three main areas affecting container throughput in the port of Busan, namely the Russia-Ukraine war, the increased competition for transshipment cargo of Chinese ports, and the weaker growth rate of the Korean economy. Based on the forecast, in order for the Port of the Port of Busan to continue to grow as a logistics hub in Northeast-Asia, policy intervention is necessary to diversify the demand for transshipment cargo and maximize benefits of planned infrastructural investments.

• 콘크리트학회지
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• 제8권3호
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• pp.147-155
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• 1996

본 연구에서는 미세역학모델을 이용하여 무근 콘크리트의 응력-변형도관계를 예측할 수 있는 모델을 제시하였다. 모델에서는 하중이 가해지기 전에 골재와 모르터의 경계면에 초기 균열이 존재한다고 가정하고 하중에 의한 부착균열과 모르터균열의 형성여부를판별하기 위하여 선형탄성파괴역학(LEFM) 이론을 사용하였다. 또한 계산의 편의를 위하여 이러한 부착균열-몰타균열의 결합된 형상을 등가 직선균열로 치환하여 해석하였다. 발생된 균열의 크기와 그 밀도로부터 손상된 콘크리트의 연성도와 변형의 증가량을 계산하고 발표된 실험결과와 비교하여 보았다. 그 결과 본 모델에 의한 응력-변형도 관계의 예측은 압축보다는 인장에, 보통 콘크리트보다 고강도 콘크리트에 더 잘 적용됨을 발견하였다.

• 환경영향평가
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• 제18권1호
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• pp.51-57
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• 2009

Corylopsis coreana Uyeki is endemic species in the Korean peninsula and is designated a Category Endangered Plant Species by the Wildlife Protection Act of South Korea. We developed the plan and cooperative model within the local community for the species conservation. In order to carry out this plan we first investigated the ecological characteristics of the species. The species shows patterns of discontinuous distribution and is coupled with the unusual feature of only growing on northern exposed slopes. Although Corylopsis coreana is cut the stem every year, many new sprouts are still grown from the root. Natural germination of the seed occurs only on north-facing slopes, but not on south-facing slopes at spring. That is, the species is highly influenced by soil moisture until the seedling stage has been reached. This factor limits the distribution of the species. When saplings are planted on south-facing slopes, they grow well. The information we gathered greatly helped with efforts to draw up conservation plans. In addition, when the information was shared with the local community, builders and residents showed great interest and displayed a will to help with conservation efforts. Therefore, a cooperative model within the local community was drawn up for the conservation of the species. Accordingly this model could be applied at mitigation measure at environment impact assessment.

• Journal of applied mathematics & informatics
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• 제9권2호
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• pp.459-517
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• 2002

The purpose of this paper is to provide a careful and accessible exposition of diffusive logistic equations with indefinite weights which model population dynamics in environments with strong spatial heterogeneity. We prove that the most favorable situations will occur if there is a relatively large favorable region (with good resources and without crowding effects) located some distance away from the boundary of the environment. Moreover we prove that a population will grow exponentially until limited by lack of available resources if the diffusion rate is below some critical value; this idea is generally credited to Thomas Malthus. On the other hand, if the diffusion rate is above this critical value, then the model obeys the logistic equation introduced by P. F. Verhulst .

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.905-910
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• 2003

In this paper, we develop real-time monitoring system to detect third-party damage on natural gas pipeline by using sound propagation model. Since many third-party incidents cause damage that does not lead to immediate rupture but can grow with time, the developed real-time monitoring system can execute a significant role in reducing many third-party damage incidents. The developed system is composed of three steps as follows: i) DSP based system, ii) wireless communication system, iii) the calculation and monitoring software to detect the position of third-party damage using the propagation speed of acoustic wave. Furthermore, the developed system was set at practical offshore pipeline between two islands in Korea and it has been operating in real time.

• Journal of Information Technology Applications and Management
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• 제13권2호
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• pp.17-28
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• 2006

The SRGM has been studied under the assumption that S/W reliability can grow as the fault causing failure is removed even during operational phase because the debugging is available. On the other hand, some papers insist on the uniform failure rate during operational phase because the debugging may not be available in case of universal software. The phenomenon, however, has been observed informally many times that the products S/W reliability grows as the time goes by even without any debugging in point of customer view. I propose the simple approaching method to model the S/W reliability phenomenon that the failure rate reduces as time goes on without modifying the existing reliability model in this paper.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2004년도 추계학술대회
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• pp.272-273
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• 2004

Filter media are one of themost important choices when bilfiltration is applied. Filter media provide adsorbing microbes with available sites for residence and the residential cells grow to degrade or decompose target waste gases. Up to date, filter media were only qualitatively analyzed. As a quantitative approach to filter material for biofiltration, a simple model based on reaction kinetics and mass action law (Ottengraf's Model in 1983) was presented. Cork, zeolite, and granulated activated carbon were tested in terms of effective surface area, cell covered fraction of adsorbing sites, surface roughness, and pore size distribution. The cell covered fraction, surface roughness and hydrophilicity was found to be closely related to the efficiency of gas degradation in biofiltration. The cork was the best candidate for cell residence and growth in this work.

• Journal of Information Science Theory and Practice
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• 제6권1호
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• pp.18-30
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• 2018

Interest in open data is continuing to grow around the world. In particular, open government data are considered an important element in securing government transparency and creating new industrial values. The South Korean government has enacted legislation on opening public data and provided diversified policy and technical support. However, there are also limitations to effectively utilizing open data in various areas. This paper introduces an administrative district knowledge model to improve the sharing and utilization of open government data, where the data are semantically linked to generate a knowledge graph that connects various data based on administrative districts. The administrative district knowledge model semantically models the legal definition of administrative districts in South Korea, and the administrative district knowledge graph is linked to data that can serve as an administrative basis, such as addresses and postal codes, for potential use in hospitals, schools, and traffic control.