• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.333-337
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• 1994

In order to develop the whey beverage, we examined the optimum conditions for alcohol fermentation by Kluyveromyces tragilis ATCC 46537. The optimum conditions for alcohol production by K. fragilis ATCC 46537 were as follows; pH 4.5, $30^{\cir}C$, with a supplement of 50 g/l of lactose. To develop a continuous production of alcohol from whey, we compared batch fermentation with continuous iermentation in conjunction with UF system. Batch fermentation produced 11.0 g/l of alcohol, whereas pseudocontinuous and continuous fermentation with UF system produced 8.5 g/l of alcohol. To increase the alcohol production, we added 50 g/l of lactose to both fermentations. Batch fermentation with lactose supplement produced 15.7 g/l of alcohol and continuous fermentation with lactose supplement in conjunction with UF system produced 15.0 g/l of alcohol. These results clearly demonstrate that the UF system can be used to increase the alcohol production from whey, supplemented with exogenous lactose.

• Journal of information and communication convergence engineering
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• v.16 no.2
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• pp.93-98
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• 2018

The Internet of Things (IoT) is a form of the emerging 4th industry in the 5G era. IoT is expected to develop naturally in our daily life in the 5G era in which high-speed communication will be completed. Along with the rise of IoT, concerns about security and malicious attacks are also increasing. This paper examines DoS attacks, which are one of the representative security threats of IoT and proposes a local detection and blocking system that are suitable for response to such attacks. First, systems of the LoRaWAN type, which are most actively researched in the IoT system field and DoS attacks that can occur in such systems were examined. Then, the inverse order tree algorithm using regional characteristics was designed as a cluster analysis form. Finally, a system capable of defending denial-of-service attacks in the 5G IoT system using local detection and blocking with the Euclidean distance was designed.

• Bulletin of the Korean Mathematical Society
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• v.32 no.2
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• pp.163-170
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• 1995

Let G be a Lie group with Lie algebra L(G) and let $\Omega$ be a nonempty subset of L(G). If $\Omega$ is interpreted as the set of controls, then the set of elements attainable from the identity for the system $\Omega$ is a subsemigroup of G. A system $\Omega$ is called a non-overlapping control system if any element attainable for $\Omega$ is only attainable at one time.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1641-1642
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• 2015

Recently, the interest about Vehicle-to-Grid(V2G) system which can use the electric vehicles as generation sources or storage devices has rapidly increased. However, this technology does not use widely yet, and there is no clear standard or regulation for it. If electric vehicles are connected to the power system indiscreetly, it can cause problem to personnel safety and adverse effect on the power system. Therefore, it is important to analyze the related standards. In this paper, we introduce some international standard related with V2G system.

• Spatial Information Research
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• v.10 no.4
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• pp.567-578
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• 2002

The success of gCRM depends on the availability of adequate, real-time data about customers' location and the provision of diverse value-added services utilizing it. In the existing gCRM systems, however, it seems that the positional precision of customers' location is very low, and further that the services based on real-time location data are not provided. In order to overcome these weaknesses and extend the limited scope of gCRM, we suggest a new design of gCRM system integrated with LBS. We also describe in some detail the system prototype for such an integration.

• Journal of applied mathematics & informatics
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• v.22 no.1_2
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• pp.435-440
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• 2006

Let G be a simple graph with vertex set V(G) and edge set E(G). A subset S of E(G) is called an edge cover of G if the subgraph induced by S is a spanning subgraph of G. The maximum number of edge covers which form a partition of E(G) is called edge covering chromatic number of G, denoted by X'c(G). It is known that for any graph G with minimum degree ${\delta},\;{\delta}-1{\le}X'c(G){\le}{\delta}$. If $X'c(G) ={\delta}$, then G is called a graph of CI class, otherwise G is called a graph of CII class. It is easy to prove that the problem of deciding whether a given graph is of CI class or CII class is NP-complete. In this paper, we consider the classification of nearly bipartite graph and give some sufficient conditions for a nearly bipartite graph to be of CI class.

• Korean Journal of Mathematics
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• v.18 no.4
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• pp.473-487
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• 2010

We investigate the existence of multiple nontrivial solutions (${\xi}$, ${\eta}$) for perturbations $g_1$, $g_2$ of the harmonic system with Dirichlet boundary condition $${\Delta}^2{\xi}+c{\Delta}{\xi}=g_1(2{\xi}+3{\eta})\;in\;{\Omega}\\{\Delta}^2{\eta}+c{\Delta}{\eta}=g_2(2{\xi}+3{\eta})\;in\;{\Omega}$$ where we assume that ${\lambda}_1$ < $c$ < ${\lambda}_2$, $g^{\prime}_1({\infty})$, $g^{\prime}_2({\infty})$ are finite. We prove that the system has at least three solutions under some condition on $g$.

• Journal of applied mathematics & informatics
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• v.27 no.5_6
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• pp.1157-1163
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• 2009

Let G be a graph with vertex set V(G) and let f be a nonnegative integer-valued function defined on V(G). A spanning subgraph F of G is called a fractional f-factor if $d^h_G$(x)=f(x) for all x $\in$ for all x $\in$ V (G), where $d^h_G$ (x) = ${\Sigma}_{e{\in}E_x}$ h(e) is the fractional degree of x $\in$ V(F) with $E_x$ = {e : e = xy $\in$ E|G|}. In this paper it is proved that if ${\delta}(G){\geq}{\frac{b^2(k-1)}{a}},\;n>\frac{(a+b)(k(a+b)-2)}{a}$ and $|N_G(x_1){\cup}N_G(x_2){\cup}{\cdots}{\cup}N_G(x_k)|{\geq}\frac{bn}{a+b}$ for any independent subset ${x_1,x_2,...,x_k}$ of V(G), then G has a fractional f-factor. Where k $\geq$ 2 be a positive integer not larger than the independence number of G, a and b are integers such that 1 $\leq$ a $\leq$ f(x) $\leq$ b for every x $\in$ V(G). Furthermore, we show that the result is best possible in some sense.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.514-516
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• 2005

This paper presents the performance results of roof-integrated 3kW PV (Photovoltaic) system by field testing. Form these results, the loss factors of PV system are compared and analyzed.

• Journal of the Korean Society of Tobacco Science
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• v.36 no.1
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• pp.20-25
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• 2014

As part of a balanced testing battery, subchronic inhalation studies on rats are performed to ensure that proposed cigarette modifications do not increase the toxicity of smoke and to demonstrate any instances where a modification may actually contribute to harm reduction. For subchronic inhalation studies with aerosols, the OECD suggests an exposure regimen of 6 hours/day (OECD Guideline 413, 1981), but alternative regimens have also been published: 1 hour/day and $2{\times}1$ hour/day. The aim of this study was to validate a rodent nose-only exposure system for the assessment of inhalation toxicity of cigarette smoke. In this study, cigarette smoke exposure system is consisted of cigarette smoke generator, smoke concentration adjusting system, and 20-port nose-only exposure system. Male SD rats were exposed for 35 days ($2{\times}1$ hour/day) to 3R4F Reference cigarette smoke and analysed major monitoring items of OECD Gudeline 413. WTPM, was measured in the test atmosphere, respiratory function (Buxco Biosystems) during exposure, postexposure urinary exposure biomarkers and alveolar neutrophiles in BAL fluid (Day 35) were evaluated. Validation demonstrated steady WTPM ($257{\pm}20ug/L$, $502{\pm}27ug/L$) and spatial uniformity (<10%). Nose port temperature ($22{\sim}26^{\circ}C$ and RH (45~75%) were acceptable over 35 days. Reductions in respiratory rate and minute volume and increase in the neutrophiles in BALF and the urinary exposure biomarkers were observed cigarette smoke dose dependently. This validation and 35-day inhalation study has shown that the rodent nose-only exposure system may be useful in the inhalation toxicity assessment of cigarette smoke.