• Geomechanics and Engineering
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• 제17권5호
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• pp.485-496
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• 2019

Sealing of leakage in waterfront or water-retaining structures is one of the major issues in geotechnical engineering practices. With demands for biological methods as sustainable ground improvement techniques, bioclogging, defined as the reduction in hydraulic conductivity of soils caused by microbial activities, has been considered as an alternative to the chemical grout techniques for its economic advantages and eco-friendliness of microbial by-products. This study investigated the feasibility of bioaugmentation and biostimulation methods to induce fermentation-based bioclogging effect in coarse sands. In the bioaugmentation experiments, effects of various parameters and conditions, including grain size, pH, and biogenic gas generation, on hydraulic conductivity reduction were examined through a series of column experiments while Leuconostoc mesenteroides, which produce an insoluble biopolymer called dextran, was used as the model bacteria. The column test results demonstrate that the accumulation of bacterial biopolymer can readily reduce the hydraulic conductivity by three-to-four orders of magnitudes or by 99.9-99.99% in well-controlled environments. In the biostimulation experiments, two inoculums of indigenous soil bacteria sampled from waterfront embankments were prepared and their bioclogging efficiency was examined. With one inoculum containing species capable of fermentation and biopolymer production, the hydraulic conductivity reduction by two orders of magnitude was achieved, however, no clogging was found with the other inoculum. This implies that presence of indigenous species capable of biopolymer production and their population, if any, play a key role in causing bioclogging, because of competition with other indigenous bacteria. The presented results provide fundamental insights into the bacterial biopolymer formation mechanism, its effect on soil permeability, and potential of engineering bacterial clogging in subsurface.

• 한국전문물리치료학회지
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• 제26권2호
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• pp.69-75
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• 2019

Background: Knee osteoarthritis (OA) diagnosis using Kellgren-Lawrence scores is commonly used to help decision-making during assessment of the severity of OA with assessment of pain, function and muscle strength. The association between Kellgren-Lawrence scores and functional/clinical outcomes remains controversial in patients with knee OA. Objects: The purpose of this study was to examine the relationships between Kellgren-Lawrence scores and knee pain associated with OA, function during daily living and sports activities, quality of life, and knee muscle strength in patients with knee OA. Methods: We recruited 66 patients with tibiofemoral knee OA and determined knee joint Kellgren-Lawrence scores using standing anteroposterior radiographs. Self-reported knee pain, daily living function, sports/recreation function, and quality of life were measured using the knee injury and OA outcome score (KOOS). Knee extensors and flexors were assessed using a handheld dynamometer. We performed Spearman's rank correlation analyses to evaluate the relationships between Kellgren-Lawrence and KOOS scores or muscle strength. Results: Kellgren-Lawrence scores were significantly negatively correlated with KOOS scores for knee pain, daily living function, sports/recreation function, and quality of life. Statistically significant negative correlations were found between Kellgren-Lawrence scores and knee extensor strength but not flexor strength. Conclusion: Higher Kellgren-Lawrence scores were associated with more severe knee pain and lower levels of function in daily living and sports/recreation, quality of life, and knee extensor strength in patients with knee OA. Therefore, we conclude that knee OA assessment via self-reported KOOS and knee extensor strength may be a cost-effective alternative to radiological exams.

• 지식경영연구
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• 제23권1호
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• pp.1-26
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• 2022

소셜 네트워크의 확산에 따라 플랫폼을 기반으로 한 소셜커머스는 다중 스마트 기기의 사용과 함께 빠르게 성장해왔다. 쿠팡과 티켓몬스터와 같은 소셜커머스 사이트들의 빠른 성장을 감안한다면 소셜커머스 환경에서 사용자의 구매 의사 결정 과정을 이해하는 것은 매우 중요하다. 본 연구의 목적은 첫째, 소셜커머스를 이용하는 사용자들의 목표에 대한 이해를 보다 풍부하게 발전시키고자 한다. 둘째, 사용자의 목표를 분석하기 위한 방법론적 대안을 소개한다. 본 연구에서는 래더링 인터뷰와 수단-목적사슬 분석을 활용했다. 소셜커머스를 활용한 구매 경험이 6개월 이상인 사용자 40명을 대상으로 실시한 인터뷰 분석 결과, 사용자의 목표 구조를 보여주는 위계적 목적지도가 도출되었다. 본 지도는 타인과의 따뜻한 관계, 쇼핑의 재미와 즐거움, 성취감, 만족감, 금전적 저축, 편의성 등을 포함한 소셜커머스의 22가지 궁극적인 목표를 담고 있다. 또한 활동에서부터 궁극적인 목표까지 다양한 경로가 존재하기에 사용자가 추구하는 목표를 조사하면 사용자를 이해하는 통찰력을 얻을 수 있다.

• 한국컴퓨터정보학회논문지
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• 제27권2호
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• pp.145-151
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• 2022

본 연구는 현대를 살아가는 사람들이 생애주기별로 받는 스트레스 해소와 사회성 증진을 돕는 소셜미디어 플랫폼에 대해 알아보고자 하였다. 연구방법은 생애주기별 스트레스 특성과 사회성 그리고 소셜미디어에 대해 문헌적 연구를 하였다. 결과 현대를 살아가는 사람들은 생애주기별로 청소년기 중년기 노년기 등 다양한 스트레스 상황에 놓여 있으며, 특히 우리나라의 스트레스 지수는 점점 높아 지고 있다. 그 스트레스를 해결하기 위한 대처 방안으로 인터넷 기반의 소셜미디어 플랫폼을 활용하여 다양한 정보제공 및 접근이 필요하다고 보았으며, 복잡하고 다양한 개인 성향들과 개인주의적 활동에 각각의 성향과 욕구에 발맞춰 성향별 플랫폼 개발과 접근성이 용이하도록 해야 할 것이며, 관련 연구가 지속적으로 이뤄져야 한다고 제언한다.

• Fisheries and Aquatic Sciences
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• 제24권10호
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• pp.319-329
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• 2021

In the search for antibiotic alternatives from safe and effective medicinal plants against fish pathogenic bacteria, we found that a combined extract (CE) of 1:1 (w/w) ratio of Angelica gigas Nakai roots and aerial parts of Artemisia iwayomogi Kitamura showed antibacterial activity against the fish pathogenic bacteria. By antibacterial activity-guided fractionations and isolations, five compounds were isolated and identified as decursinol angelate (1), decursin (2), xanthotoxin (3), demethylsuberosin (4), and 2,4-dihydroxy-6-methoxyacetophenone (5) through spectroscopic analyses, such as nuclear magnetic resonance (NMR) and mass spectrometry (MS). Among the compounds, 1 and 2 showed the highest antibacterial activities against Streptococcus iniae and Vibrio anguillarum, showing minimum inhibitory concentrations (MICs) of 62.5-250 ㎍/mL. Compounds 3, 4, and 5 were also found to be active, with MICs of 31.25-1,000 ㎍/mL for those strains. Furthermore, active compounds, 1 and 2 in CE were simultaneously quantified using high-performance liquid chromatography-tandem MS (HPLC-MS/MS). The average contents of 1 and 2 in CE was 3.68% and 6.14%, respectively. The established method showed reliable linearity (r² > 0.99), good precision, accuracy, and specificity with intra- and inter-day variations of < 2 % and recoveries of 90.13%-108.57%. These results may be helpful for establishing the chemical profile of CE for its commercialization as an antibiotic alternative in aquaculture.

• 한국안전학회지
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• 제37권2호
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• pp.35-42
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• 2022

When an accident occurs, the associated human activity is typically regarded as a "human error," or a temporal deviation. On the other hand, if the accident results in a serious loss or if it evokes a social issue, the person determined to be responsible may be punished with a "violation" of related laws or regulations. However, as Heinrich stated, it is neither appropriate nor reasonable in terms of probability theory and cognitive science to distinguish whether it is a "human error" or a "violation" with a criterion of resultant accident severity. Nonetheless, some in society get on the social climate to strengthen regulations on workers who have caused accidents, especially violations. This response can present a social issue due to the lack of systematic judgment procedure which distinguishes violations from human errors. The purpose of this study was to develop an objective and systematic procedure to assess whether workers' activities which induced industrial accidents should be categorized as violations rather than human errors. Various analysis techniques for the determination of violation procedure were investigated and compared using an analysis approach method. An appropriate technique was not found, however, for judging the culpability of intentional violations. As an alternative, this study developed the process of creating violations, based on cognitive procedure, as well as the criteria to determine and categorize an activity as a violation. In addition, the developed procedure was applied to cases of industrial accidents and nuclear power plant issues to test its practical applicability. The study demonstrated that the proposed model could be used to determine the existence of a violation even in the case of multiple workers who work simultaneously.

• 문화기술의 융합
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• 제7권4호
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• pp.807-814
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• 2021

코로나-19로 인해 경제 활동이 낮아지고 주식 시장이 침체하면서 주식 투자를 통해 또 다른 소득을 마련하기 위해 많은 사람이 주식 시장에 뛰어들고 있다. 사람들의 관심이 높아지면서 더 많은 수익을 얻기 위한 주가 분석 연구가 많이 진행되고 있다. 주가는 종목별 변동의 흐름이 다르므로 각 주가 종목별로 독립적이며 일관적으로 분석할 필요가 있다. 이러한 문제를 해결하고자 본 논문에서는 강화학습 기법 중 하나인 Asynchronous Advantage Actor-Critic(A3C)를 이용하여 주가를 분석할 수 있는 모델 및 서비스를 설계 및 구현하였다. 주식 시장 데이터로 종목별 주가 및 국채, 코스피와 같은 외부 요인들을 반영하였다. 또한 웹페이지 제작을 통해 시각화한 정보를 제공하여 투자자들이 투자 기업에 대한 재무제표를 비롯하여 국내외 경제 및 정치의 흐름을 모두 분석하지 않고도 안전한 투자를 할 수 있도록 서비스를 제공한다.

• 한국유기농업학회지
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• 제30권2호
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• pp.129-149
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• 2022

In March 2020, the National Assembly revised the Framework Act on Cooperatives, allowing a federation of heterogeneous cooperatives, and in October 2020, the Daegu Gyeongbuk Federation of Local Food Cooperatives was launched as the first federation of heterogeneous cooperatives in the country. The local food movement, which has been promoted upward in the local community as an alternative to the existing global food system, seems to be being activated by the government's food plan policy, but critics say that the government's policy goals are not fully achieved due to the top-down policy promotion and lack of communication. In response, this study first examines the role and significance of the local food federation of heterogeneous cooperatives in solving the problems raised in the process of establishing a food plan. In addition, the current status of the federation was investigated for the successful settlement and development of the Daegu Gyeongbuk Federation of Local Food Cooperatives. A survey of affiliated cooperatives, focus group interviews with managers and experts and related literature surveys were conducted. Based on this, the direction of activities was presented, such as the role of an intermediary in Daegu and Gyeongbuk and the role of an intermediary in the public and private sectors etc. In addition, six joint project tasks were specifically presented, including an integrated information sharing system & a logistics network, a planned production system & a joint processing center, an online sales system & a co-marketing promotion, a joint education system, a management of direct stores & restaurants, a sustainable public-private cooperation system etc.

• 동서간호학연구지
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• 제28권2호
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• pp.151-159
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• 2022

Purpose: This study was conducted to identify the performance and need of professional nursing care among nurses in a neurosurgery department at a tertiary hospital. Methods: This study used a descriptive design using a questionnaire with 77-item. The participants were 58 nurses with more than 3 years of clinical experience in both the neurosurgery intensive care unit and ward at a tertiary hospital in Gangwon province. Data collection was conducted from January to February of 2021. The performance and need for each workforce were analyzed with the mean and standard deviation, and the effectiveness of the difference between the performance and the need were analyzed with a paired t-test using SAS 9.4. Results: The recognition for work performance level was in order of direct nursing activities (3.20±.54), consultation and coordination (3.18±1.15), education (2.55±.85), administration (1.92±.86), and research (1.57±.89). The recognition for need level was in order of consultation and coordination (3.95±.83), education (3.91±.87), direct nursing practice (3.83±.55), research (3.49±.87), and administration (3.45±.54). The results showed a statistically significant differences between work performance and need (p<.001). Conclusion: It is required to hire professional nursing personnel who can bridge the gap between the performance and need of professional nursing workforce in a neurosurgery department at a tertiary hospital. A professional nurse may be a good alternative.

• 실천공학교육논문지
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• 제14권2호
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• pp.361-366
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• 2022

최근 가상증강현실 기술의 발달로 메타버스가 차세대 인터넷 시대를 주도할 새로운 패러다임으로 떠오르면서 사회나 경제적 활동이 게임, 엔터테인먼트, 음악, 콘텐츠 산업 등을 중심으로 확산 중이다. 더구나 코로나19 발생 이후 비대면 전환이 가속화되면서 생활양식과 산업현장이 언택트(Untact)화 되고 나아가 빠르게 메타버스화 되고 있다. 특히, 교육 분야에 메타버스 적용이 주목받고 있는데, 이는 아바타를 이용한 실시간 음성 대화, 3차원 오브젝트, 360도 영상 등을 활용하는 실감형 수업이 몰입도를 높여 원격 교육의 한계를 극복할 수 있기 때문이다. 본 연구에서는 메타버스의 개념을 살펴보고 메타버스를 활용한 교육이 비대면 시대에 교육의 효과를 높일 수 있는 대안이 될 수 있음을 고찰한다. 특히 언어교육에 효율적임을 보이고 실제 메타버스 기반 한국어 언어교육 프로그램을 제안한다.