• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.33-39
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• 2012

A numerical simulation of plume from a stack into atmospheric cross flow is investigated using a two-dimension model. The simulation is based on the ${\kappa}{\sim}{\varepsilon}$ turbulence model and a finite volume method. In this paper, it mostly researches how the wind velocity affects the flue gas diffusion from an 80 m high stack. Wind velocity is one of the most important factors for flue gas diffusion. The plume shape size, the injection height, the NO pollutant distribution and the concentration at the near ground are presented with two kinds of wind velocities, 1 m/s and 5 m/s. It is found that large wind velocity is better for flue gas diffusion, it generates less downwash. Although the rise height is lower, the pollutant dilutes faster and more sufficient.

• Journal of Nutrition and Health
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• v.44 no.4
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• pp.338-343
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• 2011

This study assessed the current EAR, RDA, and AMDR for protein, which were set in 2005 and revised in 2010 as the DRIs for Koreans. A classical approach to establish the EAR for protein has been the nitrogen balance method. This method has practical limitations and problems in statistical analysis by giving over estimations of nitrogen balance. Thus, the present EAR for protein might be lower than the true requirement. Recent reevaluations of nitrogen balance studies by bilinear regression analysis and the IAAO method have indicated that the EAR of 0.66 g/kg bw/d should be increased by 39% to give 0.92 g/kg bw/d. The AMDR for protein in the Korean DRIs was set at 7-10%, which covers almost the entire population's protein intake. Since the 5th percentile of Korean protein intake is close to 10% of energy and due to the beneficial effects of protein beyond the maintenance of nitrogen equilibrium, the lower range of 7% needs to be increased up to 10%. For practical meal arrangement, 15% of energy as protein, which is close to the average protein intake of Koreans, seems to be proper, although the value is almost two times the EAR.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.2
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• pp.39-47
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• 2010

As vehicles become intelligent for convenience and safety of drivers, in-vehicle networking (IVN) systems are essential components of intelligent vehicles. Recently, the chassis networking system which require increased network capacity and real-time capability is being developed to expand the application area of IVN systems. Also, FlexRay has been developed for the chassis networking system. However, FlexRay needs a complex scheduling method of static segment, which is a barrier for implementing the chassis networking system. Especially, if we want to migrate from CAN network to FlexRay network using CAN message database that was well constructed for the chassis networking system by automotive vendors, a novel scheduling method is necessary to be able to reduce design complexity. This paper presents a node-based scheduling method for FlexRay network system. And, in order to demonstrate the method's feasibility, its performance is evaluated through an experimental testbed.

• Journal of the Korean Chemical Society
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• v.31 no.6
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• pp.527-533
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• 1987

Kinetic studies on the complexing of aquamolybdenum(Ⅳ) trimer with thiocyanate have been carried out using the spectrophotometric method. The observed rate constant, $k_{obsd}$ is given by $k_{obsd}\;=\;{k_O + k_H[H^+]^2}(SCN^-) + k_r$. At 25$^{\circ}$C and ionic strength of 2.30 the values of $k_f$ and $k_r$ are $(3.78 {\pm} 0.61) {\times} 10^{-4}M^{-1}s^{-1}$ and $(6.93 {\pm} 2.39) {\times} 10^{-4}s^{-1}$, respectively. Activation parameters are ${\Delta}H^* = 50.71{\pm}6.91 kJmol^{-1}$ and ${\Delta}S^* = -121.65JK^{-1}mol^{-1}$. The mechanism is proposed and discussed.

• KDI Journal of Economic Policy
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• v.39 no.1
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• pp.1-18
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• 2017

This paper empirically studies the effect of public procurement on small and medium-sized enterprises (SMEs) in the Republic of Korea using firm-level data. Public procurement, the purchase of goods and services from private firms by the public sector, is regarded as an important policy measure for providing support to firms, particularly SMEs. This study uses establishment-level panel data of the mining and manufacturing sectors from the Korean National Bureau of Statistics (Statistics Korea) and procurement history from the Korean Public Procurement Service to empirically estimate the effects of public procurement on firms' productivity (total factor productivity) and survivability. Using a propensity score matching estimation method, we find that participating firms showed higher productivity than non-participating ones in the control group only for the year of participation, that is, 2009. After two years, in 2011, they exhibited significantly lower productivity. In contrast, establishments that participated in public procurement for SMEs in 2009 were more likely to survive than those that did not do so in 2011. These results can be interpreted as the negative consequences of government intervention. The market's efficiency enhancement is hindered if underserving companies survive owing to government intervention but fail to improve efficiency.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.1
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• pp.15-24
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• 2018

In this paper, we explain a method of appproximating the differentials probability using a SAT solver. It is possible to increase the probability by constructing the differential characteristic which already known to differentials with a SAT solver. We apply our method to SPECK32 and SPECK48. As a result, we introduced a SPECK32's 10-round differentials with a probability of$2^{-30.39}$, and SPECK48's 12-round differentials with probability of $2^{-46.8}$. Both differentials are new and longer round and higher probability than previous ones. Using the differentials presented in this paper, we improved attacks of SPECK32/64 to 15 round, SPECK48/72 to 16 round, SPECK48/96 to 17 round, which attack 1 more rounds of previous works.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.3
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• pp.387-395
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• 2015

Starfish, a species of Echinoderm, is widely known as a predator on benthic invertebrate. A series of fishing experiments was carried out in the western coastal waters of Korea from September, 2011 to November, 2012, using the drum-shaped pots of different mesh sizes (17.1, 24.8, 35.3, 39.8, and 48.3 mm) to describe the composition of the catch species and the mesh selectivity of the pot for starfish. Some species including fish, crab, and starfish were caught in the experimental pots. The SELECT (Share Each Length's Catch Total) method was applied to describe the selectivity of the pot for starfish Asterina pectinifera. The master selection curve was estimated to be s(R) = exp(10.358R-4.086) / [1+exp(10.358R-4.086)], where R is the ratio of arm length to mesh size. The relative arm length of 50% retention was 0.395, and the selection range was 0.212. The results should be helpful to understand the relationship between the catch size of starfish and the mesh size of pot.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.3
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• pp.284-291
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• 2014

Finely-striate buccinum Buccinum striatissimum, a species of whelks, is caught mainly by pot in the eastern coastal waters of Korea. In order to determine the size selectivity of pot for the species, comparative fishing experiments were conducted near Yeongil Bay from June to September in 2003 using the dome-shaped pots with different five mesh sizes (17.1, 24.8, 35.3, 39.8, and 48.3 mm). The parameters of logistic equation were estimated by the SELECT (Share Each Length's Catch Total) method based on a multinomial distribution. The model with the estimated split parameter was found to fit the catch data best. The master selection curve was estimated to be s (R)=exp (13.044R-16.438)/[1 + exp (13.044R-16.438)], where R is the ratio of shell height to mesh size. The relative shell height of 50% retention was 1.260, and the selection range was 0.168. Enlargement in mesh size of the pot allows more small-sized whelks to escape.

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.203-218
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• 2018

The aim of this study was to develop the Equine Assisted Activities and Therapies(EAAT) screening tool for children and adolescents, which can be available for the EAAT instructors to screen potential participants in the riding center. The preliminary screening tool was developed by six experts and several international guidelines were used for the references. A two-round Delphi study was performed with 23 experts. Panel members were asked to rate their (dis)agreement with each tool's item on an 11-point scale. The consensus was considered to be reached when the item was scored more than 8. The consensus was reached on 39 items out of 48, resulting the final screening tool's items are to be 39. The resulting screening tool could contribute to make safer EAAT settings for participants and the future investigations in adult subjects will be needed.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.1
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• pp.34-39
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• 2013

This paper proposes the implementation of robust fuzzy controller for designing intelligent wind farm and mitiagating the fluctuation of wind power generator. The existing researches are limited to individual wind turbine with variable speed so that it is necessary to study the multi-agent wind turbine power system. The scopes of these studies include from the arrangements of each power turbine to the control algorithms for the wind farm. For solving these problems, we introduce the composition of intelligent wind farm and use the T-S (Takagi-Sugeno) fuzzy model which is suitable for designing fuzzy controller. The control object in wind farm enables the minimizing the fluctuation of wind power generator. Simulation results for wind fram which is modelled as mathematically are demonstrated to visualize the feasibility of the proposed method.