• Journal of Microbiology and Biotechnology
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• 제16권4호
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• pp.590-596
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• 2006

Clavulanic acid (CA) produced by Streptomyces clavuligerus is degraded during the bacterial cultivation. The degradation was examined in three different aspects, including physical, chemical, and enzymatic effects, in order to understand the degradation during the cultivation. The result showed that CA was unstable in the production medium containing ammonium salts and amino acids, owing to ammonium ions and amine groups. In addition, the degradation was not only due to instability of CA by metabolites and proteins, but also enzymes from S. clavuligerus such as $\beta-lactamase$ and penicillin-binding proteins. However, the degradation caused by these enzymes was not highly significant compared with the degradation during the cultivation, owing to irreversible reactions between CA and enzymes.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1107-1114
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• 2005

The running condition of multi-system air conditioner is prone to vary largely as it is designed for individual conditioning in each space of middle and small sized buildings. This leads to overcooling in case of partial load run, while the lack of capacity happens in case of full load run. Besides these, there exist such problems as instabilities due to the uneven refrigerant distribution caused by fluctuation of load and the change in piping line. Based upon the basic study on the function characteristics found in parts needed for maximized system working design in order to troubleshoot, the system functioning pattern should be identified through the different tests with various operating circumstances and the analysis models should be developed. With this ground, the control logic has to be made to have a control over capacity and make possible the efficient distribution of refrigerant.

• Journal of Contemporary Eastern Asia
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• 제23권1호
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• pp.58-82
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• 2024

Former South Korean President Moon Jae-in implemented a project called the Peace Initiative, which prioritized a "peaceful and prosperous Korean Peninsula" as the core national agenda and involved using a peace-based frame instead of a unification approach to address inter-Korean relations from a different perspective. This initiative was evaluated in this study using a revised version of the pyramid model to assess the input-output-result process underlying the project and determine whether it generated results that differed from those achieved by the previous administration. To these ends, this research compared Moon's key presidential speeches with those of his predecessor, Park Geun-hye, as input, news commentaries and responses from major players as output, and the trend of perceptional and attitudinal changes in public opinion as results. Although Moon failed to accomplish significant policy effects on inter-Korean relations because of geopolitical challenges and the transfer of power to the conservative party, the analysis revealed that the input, output, and partial results of inter-Korean dialogue reflect some progress.

• Journal of applied mathematics & informatics
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• 제12권1_2호
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• pp.107-117
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• 2003

We study the integration problem in which one wants to compute the approximation to the definite integral in the average case setting. We choose the composite Newton- Cotes quadratures as our algorithm and the function values at equally spaced sample points on the given interval［0, 1］as information. We compute the average case error of composite Newton-Cotes quadratures and show that it is minimal (modulo a multi-plicative constant).

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2017년도 추계학술발표대회
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• pp.1173-1175
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• 2017

This paper proposes a system for convenient remote control and management of the lockers with a smart phone. The key features of the proposed system are as follows. First, we connect the lockers to the server and then use the authentication procedure to open and close their lockers. Second, we create instant lockers to increase convenience for users who need to use casual necessities. Unlike traditional analog methods, we finally develop certification procedures. Particularly, log data are better secured than traditional ones. The performance assessment of the proposed system is simulated by producing a dummy model. We will show that the proposed system could effectively support opening and closing the lockers using smart phones.

• 보건의료산업학회지
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• 제12권3호
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• pp.13-26
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• 2018

Objectives: This study investigated how Korean daily newspapers frame the present government's health insurance coverage expansion policy, Moon Jae-in Care. Methods: A contents analysis was conducted to construct news frames represented in the four Korean daily newspapers' editorials and columns on Moon Jae-in Care during from April 2017 to April 2018. News text was classified into three different layers of frames: expressive element, narrative structure, and implied values. Results: The analysis revealed that the frequency of narrative frames was as follows: health system improvement (20.8%), public burden (14.6%), opposition by doctors (14.6%), and populism (12.5%). The financial sustainability accounted for 41.7% of the value frame, followed by procedural legitimation (18.8%), and coverage expansion (16.7%). The results also revealed that reported frames were different among newspapers: Chosun Ilbo tended to report in a negative tone, while Hankyoreh shinmun and Kyunghyang shinmun used a positive tone. Conclusions: This finding suggests that there are salient framings in reports on Moon Jae-in Care. Based on the results, the government needs to present a detailed financing plan on Moon Jae-in Care in detail. I discussed another implication of media frames results.

• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.1928-1934
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• 2006

The rubradirin biosynthetic gene cluster harbors 58 ORFs within a 105.6-kb sequence, which includes all of the genes responsible for the synthesis of rubradirin, as well as the primary genes relevant to regulatory, resistance, and transport functions. This gene cluster also harbors a resistance-mediating ABC transporter, RubT1, which is located at the most upstream position in the cluster. In the present study, RubT1 was expressed heterologously in E. coli, and the resistance affinity of RubT1 was determined by an antibacterial activity test, as well as by HPLC and ESI-MS analyses. Evidence clearly demonstrates that RubTl mediates rubradirin resistance as an ABC transporter.

• 한국수산과학회지
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• 제54권3호
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• pp.271-279
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• 2021

Ultrasound-assisted extraction (UAE) conditions, including extraction time, extraction temperature, and ethanol concentration, were optimized to increase the total flavonoid content (TFC), tyrosinase inhibitory activity (TIA), and collagenase inhibitory activity (CIA) of Spirulina platensis through central composite design (CCD). For the optimization of the three dependent variables, a quadratic regression model was derived from 17 experimental sets for the simultaneous maximization of TFC, TIA, and CIA. The predicted optimal UAE conditions were 44.0 min of extraction time, 82.8℃ of extraction temperature, and 96.0% of ethanol concentration. Under these conditions, 0.93 mg QE/g DM of TFC, 81.9% of CIA, and 92.1% of TIA were predicted. The CCD-based UAE optimization enabled an increase in TFC, CIA, and TIA, thereby confirming that the S. platensis extract can be used in the development of a cosmetic material with skin whitening and anti-wrinkle effects.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2017년도 추계학술발표대회
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• pp.267-270
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• 2017

As IT technology developed, storage media also developed. Among them, USB, which is a removable storage medium, is used not only to have several per person but also to work in various companies. Users store valuable and confidential data within USB. As time went on, the need for security increased. In order to solve this security problem, USB has been introduced to allow users to access internal files by inputting ID and password by embedding a security program in USB. However, the method of storing ID and Password inside is low confidentiality and high risk of information leakage. To solve these problems, we propose a 2 factor authentication system using Radius server in addition to login authentication. The proposed system not only improves the authenticity of the device, but also reduces the risk of infringement of personal information when lost. It also encrypts internal files to increase the confidentiality of internal information.

• Coupled systems mechanics
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• 제7권5호
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• pp.611-626
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• 2018

We theoretically consider a possible influence of periodic oceanic tides on non-periodic changes in the dynamics of the Earth and Moon over a long time scale. A particular emphasis will be placed on the contribution from rotating tidal waves, which rotate along the inner edge of an oceanic basin surrounded by topographic boundary. We formulate the angular momentum and the mechanical energy of the rotating tidal wave in terms of celestial parameters with regard to the Earth and Moon. The obtained formula are used to discuss how the energy dissipation in the rotating tidal wave should be relevant to the secular variation in the Earth's spin rotation and the Earth-Moon distance. We also discuss the applicability of the formula to general oceanic binary planets subject to tidal coupling.