Earticle

For experimental studies on the production of MR fluid for MR dampers, MR fluid with a viscosity of 506 cP and a density of 2.6 g/cc was produced. In order for MR fluid to have suitable performance for MR dampers, it is important to select surfactants, magnetic particles, base oil, and characteristic additives to obtain high damping force and maintain physical and chemical properties. In order to investigate the redispersibility of MR fluid, viscosity, density, saturation magnetic flux density, dispersibility, and temperature effects were evaluated. A particle size distribution meter and a vibrating magnetometer were used, and a yield stress and redispersion device were developed to obtain the yield stress of the MR fluid. The recovery rate of MR fluid was approximately 97% at 0.2% succinic acid coating and 8% anti-settling agent. And when current is applied, the viscosity increases by more than 90% due to magnetic properties.

In this study, a mixed resin containing Bis-GMA was developed to produce a light-emitting sign using quantum dots. As a result of measuring the viscosity, color coordinates change, and luminance of the mixed resin, the following conclusions were obtained. The viscosity of the mixed resin decreased as the content of the diluent increased, and viscosity values ​​ranged from 3,627 to 1,349cps showed as a result. The viscosity of the mixed resin decreased as the temperature increased, and the viscosity showed a value of 5,156 to 1,132cps. For the optical properties of InP/GaP/ZnSe/ZnS quantum dots, the absolute quantum efficiency was 91% at 522nm and 90% at 618nm when the gallium was 0.01%. The luminance of the light-emitting sign using the resin mixed with quantum dots was showed 142.6cd/m2 in white and 104.2cd/m2 in the red region.

The objective of this study was to investigate the effect of different feed inoculation method on rumen fermentation in an in vitro. Three experimental treatments were used: control (CON, direct dispersion of feed (2 g) in rumen fluid), combinations of direct dispersion (1 g) and nylon bag (DNB, pore size: 50 μm, 1 g), and nylon bag (NB, 2 g). An in vitro fermentation experiment was carried out using strained rumen fluid for 48 h incubation time and timothy was used as a substrate. At the end of the incubation, in vitro dry matter digestibility (IVDMD), in vitro neutral detergent fiber digestibility (IVNDFD), pH, volatile fatty acids (VFA), ammonia nitrogen (NH3-N), and microbial community were evaluated and gas production was estimated at 3, 6, 12, 24, 48 h incubation periods. Gas production was higher in CON than DNB and NB at 6 and 12 h incubation time (p<0.01). There were no differences in final gas production, pH, NH3-N concentration, total VFA production, and VFA profiles among treatments. The IVDMD was lowest in CON (p<0.01) but the IVNDFD was not differed by feed distribution methods. There were no significant differences in general bacteria and fungi. Protozoa count was highest in NB treatment among treatments (p<0.01). The abundance of cellulolytic bacteria, Ruminococcus flavefaciens and Fibrobacter succinogenes, was highest in the CON among treatments (p<0.01).

This study was successfully achieved out the optimized system for dispersing and mixing condition of resin liquid. The flow analysis was simulated according to the shape of the impeller and the stirring tank using ANSYS software and optimized in advanced design. As a result, it was confirmed that the shape and double number of the impeller on the flow field are influenced better effects in a range of mixing and diffusion areas comparing to single number of impeller. It was considered that stirring was performed more quickly and efficiently under the condition of double numbers and saw tooth type impeller. This result can be applied practically for the mixing tank in the industrial application and avaliable used to make a new system for painting equipment.

이 연구를 통하여 조선후기 이후 어떤 이유로 오륙도가 특별한 국가적 관심을 얻게 되었으며, 근대 이후 국민적 관심까지 모으면서 오늘날의 오륙도 이미지를 구축해왔는지 살폈다. 정리하면, 요컨대, 조선후기에 선명하게 자신의 이름을 기록에 올린 오륙도의 어원에 대해선 기왕에는 조수설, 숫자설, 시각설, 방향설, 원근설 등 다양한 설이 제기 되고 있다. 하지만 그러한 이해가 오륙도가 가지는 단편적인 외형적 특성이나 오륙도에 대한 심미적 호기심에서 발동한 것은 아니었다. 조선후기 오륙도에 대한 국가적인 관심을 키우고 다양한 사서에 그 이름을 올리게 된 요인을 보면 다음과 같다. 첫째, 조선후기 오륙도에 대한 국가적인 관심은 (1) 조선의 침략하는 일본군을 저지하는 海防基地라는 측면 (2) 일본과의 교린 과정에서 양국사신의 입출국 이정표라는 측면 (3) 풍랑이 거세 항해가 무척 어려웠던 苦海의 중앙에 위치하고 있었다는 측면에서 비롯되었다. 한편, 근대사회에 들어서 오륙도는 (1) 일본의 경제적 침략을 목도하는 등대라는 의미에서 (2) 민족 이산과 재회의 이정표라는 새로운 의미가 추가되었다. 즉, 개항기에는 오륙도 인근의 어장에 대한 일본인 어민들의 무단 불법 조업과 그에 대한 조선정부의 저항(1888) 그리고 일제강점기에는 대륙침략에 필요한 물자 수송의 원활을 위한 등대 설치(1936) 등이 그 예이다. 또한 해방 후에는 귀국하는 수많은 동포들을 반겨주는 고향집 사립문과 같은 이미지도 부각되었다. 요컨대, 오륙도라는 이름의 형성에는 단순한 외형적 특징이나 조수간만 등의 피상적 요인이 아니라 조선후기 일본과의 교린 관계 회복이나 해방이라는 문제가 절실한 시대적 과제였고, 이러한 사회적 기운에 힘입어 오륙도는 ‘海防의 식별표’ 혹은 ‘交隣의 이정표’로서 그 이미지를 형성하게 되었고, 이후 일제 침략과 해방 그리고 분단의 역사 속에서 수탈의 목격자 혹은 민족 이산과 재회의 이정표라는 이미지를 더하게 된 것으로 본다.

The aim of this Research is to clarify that why aroused the national interest and public attention on oryukdo and appeared the name in history map and book for the first time in the early late 18century. Traditionally, the Japanese people saw that Oryukdo was named by tides(So called, theory of tides or number). Incidentally, at that time the elite Koreans believed that the island numbers was changing on the viewing angle(So called, theory of angle or distance). However, these days scholar’s understanding of such theory was very fragmented. Such kind of understanding was not played in fragmented or superficial characteristics or curious about the aesthetic. To summarize, the naming of Oryukdo was provided for rapid changes of the international situation(specially the Korea-Japan relation-ship in the late Chosŏn dynasty period. There are three historic reasons for this naming-process. In other words, Oryukdo name has incorporated the hope of Chosŏn dynasty (1)to stop the Japanese invasion (2)to keep friendly relations with Japan (3)to fight desperately the fear of storm around this. In the Korean modern society, it were added the new image such as (1)lighthouse which observed the japanese economic invasion. (2)milestones which gazed at the reunion the separated brothers. After the liberation(1945), adding the new image which look like brushwood-door in the Cottage home on the separated for home. These historic demands would have made the name and image on Oryukdo of today. Due to the historical request, Oryukdo could create the image of ‘the strategy point on coastal defense’ and ‘milestone for good-neighbor diplomacy’ in the late Chosŏn dynasty period. And historic changes of the colonial aggression, liberation and division in 20century, Oryukdo could add the image of ‘the exploitation of the witnesses’ and ‘milestones of nation-disperse and reunion’.

Actual type of aggregation performed by an ordered weighted averaging (OWA) operator heavily depends upon the weighting vector. A number of approaches have been suggested for obtaining the associated weights. In this paper, we present analytic forms of OWA operator weighting functions, each of which has such properties as rank-based weights and constant value of orness, irrespective of number of objectives aggregated. Specifically, we propose four analytic forms of OWA weighting functions that can be positioned at 0.25, 0.334, 0.667, and 0.75 on the orness scale. The merits for using these weights over other weighting schemes can be mentioned in a couple of ways. Firstiy, we can efficiently utilize the analytic forms of weighting functions without solving complicated mathematical programs once the degree of orness is specified a priori by decision maker. Secondly, combined with well-known OWA operator weights such as max, min, and average, any weighting vectors, having a desired value of orness and being independent of the number of objectives, can be generated. This can be accomplished by convex combinations of predetermined weighting functions having constant values of orness. Finally, in terms of a measure of dispersion, newly generated weighting vectors show just a few discrepancies with weights generated by maximum entropy OWA.

Previous researches focus on examining only the relation between cross-sectional earnings forecast dispersion and stock returns and on providing explanations for the negative dispersionreturn relation. This paper attempts to examine how time-series mean forecast dispersion is distinct in the relation to stock returns from the cross-sectional forecast dispersion effect. We find that contrary to the standard analyst dispersion effect, there is a strong positive relation between time-series mean forecast dispersion and stock returns. We also find that time-series mean forecast dispersion apparently contains systematic risk components and that such risk is priced in stock returns.

This paper empirically finds that dispersion of beliefs about the business cycle matters in asset pricing. We construct dispersion of beliefs as the log of cross-sectional dispersion of real GDP forecasts. This measure positively predicts macroeconomic volatility and the investment opportunity set, and lowers down asset prices. In the cross-section, we show that macroeconomic uncertainty is negatively priced. Additionally, the portfolio sorting approach yields 5.2% of the return spread annually, and in turn reveals that stocks less correlated with dispersion of beliefs earns higher returns. Overall evidence highlights the importance of the uncertainty underlying the fluctuation of the economy in asset pricing.

Background: This study evaluated the atmospheric dispersion of radioactive material according to local weather conditions and emission conditions. Materials and Methods: Local weather conditions were defined as 8 patterns that frequently occur around the Kori Nuclear Power Plant and emission conditions were defined as 6 patterns from a combination of emission rates and the total number of particles of the 137Cs, using the WRF/HYSPLIT modeling system. Results and Discussion: The highest mean concentration of 137Cs occurred at 0900 LST under the ME4_1 (main wind direction: SSW, daily average wind speed: 2.8 ms-1), with a wide region of its high concentration due to the continuous wind changes between 0000 and 0900 LST; under the ME3 (NE, 4.1 ms-1), the highest mean concentration of 137Cs occurred at 1500 and 2100 LST with a narrow dispersion along a strong northeasterly wind. In the case of ME4_4 (S, 2.7 ms-1), the highest mean concentration of 137Cs occurred at 0300 LST because 137Cs stayed around the KNPP under low wind speed and low boundary layer height. As for the emission conditions, EM1_3 and EM2_3 that had the maximum total number of particles showed the widest dispersion of 137Cs, while its highest mean concentration was estimated under the EM1_1 considering the relatively narrow dispersion and high emission rate. Conclusion: This study showed that even though an area may be located within the same radius around the Kori Nuclear Power Plant, the distribution and levels of 137Cs concentration vary according to the change in time and space of weather conditions (the altitude of the atmospheric boundary layer, the horizontal and vertical distribution of the local winds, and the precipitation levels), the topography of the regions where 137Cs is dispersed, the emission rate of 137Cs, and the number of emitted particles.

We propose an index of geo-linguistic dispersion that measures the extent to which spatial distribution of a socio-economic attribute is dispersed or clustered. Differently from the existing statistics measuring the extent of clustering such as e.g. Moran’s I (1948), the attribute does not have to be measurable even in the partial ordering sense. Our index is also different from Greenberg’s (1956) index of linguistic diversity since the latter is invariant with respect to the spatial distribution of languages. Our index decreases with the opportunity costs of traveling, and with the extent to which a particular attribute is geographically clustered. We envision applying the GLD index in the studies examining the associations between socio-economic outcomes, and the extent to which the values of a socio- economic attribute are diverse and geographically dispersed or clustered.

Background: This study analyzes the differences in the annual averaged atmospheric dispersion factor and ground deposition factor produced using two classification methods of atmospheric stability, which are based on a vertical temperature difference and the standard deviation of horizontal wind direction fluctuation. Materials and Methods: Daedeok and Wolsong nuclear sites were chosen for an assessment, and the meteorological data at 10 m were applied to the evaluation of atmospheric stability. The XOQDOQ software program was used to calculate atmospheric dispersion factors and ground deposition factors. The calculated distances were chosen at 400 m, 800 m, 1,200 m, 1,600 m, 2,400 m, and 3,200 m away from the radioactive material release points. Results and Discussion: All of the atmospheric dispersion factors generated using the atmospheric stability based on the vertical temperature difference were shown to be higher than those from the standard deviation of horizontal wind direction fluctuation. On the other hand, the ground deposition factors were shown to be same regardless of the classification method, as they were based on the graph obtained from empirical data presented in the Nuclear Regulatory Commission’s Regulatory Guide 1.111, which is unrelated to the atmospheric stability for the ground level release. Conclusion: These results are based on the meteorological data collected over the course of one year at the specified sites; however, the classification method of atmospheric stability using the vertical temperature difference is expected to be more conservative.

Infomediary, playing an important role in e-commerce, provides refined a product information and the price dispersion of product. This paper use the elaboration likelihood model to explain how level of involvement with a product moderates the impact of price dispersion and product information quality on product attitude. The study produces three major findings : (1) the quality of product information produced by infomediary has a positive effect on consumers' product attitude, (2) For low-involvement consumer, price dispersion of product positively affect consumers' product attitude. For high-involvement consumer, negatively affect, (3) low-involvement consumer are affected by the price dispersion rather than the quality of product information, but high-involvement consumer are affect by price dispersion mainly when the quality of product is low. These finding have implications for on-line infomediaries in terms of how to manage their users.