• Journal of Korean Society on Water Environment
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• v.21 no.4
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• pp.337-346
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• 2005

An MSBR using a membrane for not only filtration but also aeration (MA-MSBR) was designed to reduce membrane fouling and to enhance water quality, and compared with an MSBR using a membrane for only filtration (BA-MSBR). COD removal efficiency of the MA-MSBR was similar to that of the BA-MSBR, but membrane performance of the MA-MSBR was better than that of the BA-MSBR. The MA-MSBR had more small particles in mixed liquor, so the specific cake resistance of flocs in the MA-MSBR was higher than that in the BA-MSBR. However, in the aerobic reaction step of the MA-MSBR, air went through membrane pores and out of the membrane surface, so cake layers on the membrane surface and a portion of organics adsorbed on membrane pores could be removed periodically. Therefore, cake resistance, $R_c$, and fouling resistance by adsorption and blocking, $R_f$, for the MA-MSBR increased more slowly than those for the BA-MSBR. Additionally, in order to compare the energy efficiency for two MSBRs, oxygen transfer efficiency and power to supply air into the reactor by a membrane module and a bubble stone diffuser were measured using deionized water. From these measurements, the transferred oxygen amount per unit energy was calculated, resulting that of MA-MSBR was slightly higher than that of BA-MSBR.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.12
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• pp.1128-1138
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• 2010

One of the typical problems in the precise vibration is resonance characteristics at low frequency disturbance due to a heavy mass. An electro-magnetic(EM) air spring is a kind of vibration control unit and active isolator. The EM air spring in this study aims at removing the low frequency resonance for semiconductor manufacturing. The mechanical and electronic parts in the active isolator are designed to operate under a weight of 2.5 tons. The EM spring is floated using air pressure in a pneumatic elastic chamber and actuated by EM levitation force. The actuator consists of a EM coil and a permanent magnetic plate which are installed inside of the chamber. An air mount was constructed for the experiment with a stone surface plate, 4 active air springs, 4 gap sensors, a DSP controller, and a multi-channel power amp. A PD control method and operating logic was applied to the DSP. Simulation using 1/4 model was carried out and compared with the experiments. The time duration and maximum peak at resonance frequency can be reduced sharply by the proposed system. The results show that the active system can avoid the resonance caused by the natural frequency of the passive system.

• Explosives and Blasting
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• v.9 no.4
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• pp.3-12
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• 1991

The cautious blasting works had been used with emulsion explosion electric M /S delay caps. Drill depth was from 3m to 6m with Crawler Drill 70mm on the calcalious sand stone (soft-moderate-semi hard Rock) . The total numbers of feet blast were 88. Scale distance were induces 15.52-60.32. It was applied to Propagation Law in blasting vibration as follows .Propagtion Law in Blasting Vibration V=k(D/W/sup b/)/sup n/ where V : Peak partical velocity(cm/sec) D : Distance between explosion and recording sites(m) W ; Maximum Charge per delay -period of eight milliseconds or more(Kg) K : Ground transmission constant, empirically determind on the Rocks, Explosive and drilling pattern ets. b : Charge exponents n : Reduced exponents Where the quantity D/W/sup b/ is known as the Scale distance. Above equation is worked by the U.S Bureau of Mines to determine peak particle velocity. The propagation Law can be catagrorized in three groups. Cabic root Scaling charge per delay Square root Scaling of charge per delay Site-specific Scaling of charge delay Charge and reduction exponents carried out by multiple regressional analysis. It's divided into under loom and over loom distance because the frequency is varified by the distance from blast site. Empirical equation of cautious blasting vibration is as follows. Over 30m--under 100m----V=41(D/ W)/sup -1.41/-----A Over l00m---------V=121(D/ W)/sup -1.56/-----B K value on the above equation has to be more specified for furthur understand about the effect of explosives. Rock strength, And Drilling pattern on the vibration levels, it is necessary to carry out more tests.

• Journal of Technologic Dentistry
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• v.34 no.3
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• pp.213-220
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• 2012

Purpose: The aim of this study was to determine the repeatability and reproducibility of two dental scanners. Methods: The master die and the stone replicas(Kavo, Germany) were digitized in touch-probe scanner(Incise, Renishaw, UK), white light scanner(Identica, Medit, Korea) to create 3-dimensional surface-models. The number of points in the point clouds from each reading were calculated and used as the CAD reference model(CRM). Discrepancies between the points in the 3-dimensional surface models and the corresponding CRM were measured by a matching-software(Power-Inspect R2, Delcam Plc, UK). The t-student test for one samples were used for statistical analysis. Results: The reproducibility of both scanner was within $3{\mu}m$, based on mean value. The mean value between measurements made directly on the touch probe scanner digital models and those made on the white light scanner digital models was $2.20-2.90{\mu}m$, and was statistically significant(P<0.05). Conclusion: With respect to adequate data acquisition, the reproducibility of dental scanner differs. Three-dimensional analysis can be applied to differential quality analysis of the manufacturing process as well as to evaluation of different analysis methods.

• Journal of the Korea Computer Industry Society
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• v.3 no.3
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• pp.259-270
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• 2002

In computer Go, the method evaluating the situation of a face is not generalized. To evaluate the situations all the faces accurately, computer Go must judge owners of 361 positions according the changes of the faces. In this paper, we apply the structure of graph as a method analyzing the rules and characters of Go. The Situation Evaluation System(SES) which can evaluate the situation of a face without DB information oかy using strength of stone(SS), influence power(IP), safety(S), position value(PV), and position-value matrix(PM) is proposed. This system is very effective to evaluate the whole situations of Go because it can show the owner of 361 positions between Black and White. As a result, SES can well compute the situations in the opening game of Go. It makes 70.9% hit-ratio as compared with the practical Go games of professional players. According to the results compared with Nemesis, the commercial program which has the joseki(established stones: hewn sequences of moves near the corner which result in near-equal positions for White and Black), SES is superior to Nemesis by 10% higher in the hit-ratio of situation evaluations of professional players.

• Cross-Cultural Studies
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• v.23
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• pp.265-293
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• 2011

This study focused on the literary world of T. Tolstaya, a Russian writer who takes a crucial position in contemporary Russian literature, drawing upon the wrier's a couple of short stories. 'Youth' is a key motive encompassing all works of Tolstaya, so that it becomes the poetic keynote among her literary works. In order to examine such distinctions of the main characters' world awareness in their youth as shown in Tolstaya's literary works, Chapter 2 of this paper paid a special attention to the analyse of her representative works such as "Sitting on a Golden Terracing Stone" and "Meeting with a Bird", and expressed potential implications of youth with mimetic imagination for her. For Tolstaya, youth is perceived as a paradise but original imagination of youth gradually fades away in adult and ends up with a lost paradise. This is why Tolstaya uses poetic means based on nostalgia for youth like paradise and literary motto for recovery of imagination in youth. In this regard, this study particularly examined the retrospective prologue resisting the power of time as well as different fictional characters living in her own fantastic world. As a result, this study draws a conclusion that such longing and nostalgia for youth and lost paradise as delineated by Tolstaya through retrospective prologue and characters speak for an existential speculation that explores any profound implication of afflictions in reality of human life, rather than focusing on the painful reality of human life which consists of honest dialogues with realities like 'darkness' and 'pain.' In addition, this study, complying with Zolotonosov's ideas which deal with and define Tolstaya's literary works as a shabby and humble box invisibly containing a full wealth of precious jewels inside, sheds a new light on the writer's literary world.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.383-392
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• 2022

Mokpo is a port city in the southwest of the Korean Peninsula. The popular song "Tears of Mokpo" is a song planted in the hearts of the entire nation. In this content, there are Yudalsan Mountain and Samhakdo Island in Mokpo, and people vaguely know this area, but it is a familiar place. In particular, Samhakdo Island is a representative brand that symbolizes Mokpo and is a place with regional identity. Mokpo City is creating many facilities infrastructure to develop Samhakdo Island. It is a stepping stone for converting the local economy into a tourism industry. However, the development of performance contents for the soft power of local culture is weak. In this respect, this study presented performance contents for Samhakdo Island, Mokpo's representative brand, for local tourism attractiveness. The research progress is a study on planning and researching performance contents using the location of Samhakdo Island in Mokpo. First, the background of the theory of performance content planning based on local placeability was examined. Next, Samhakdo Island in Mokpo proposed planning for performance contents.

• Geomechanics and Engineering
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• v.28 no.5
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• pp.505-520
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• 2022

In recent years, geotextile-encased gravel columns (usually called stone columns) have become a popular method to increasing soil shear strength, decreasing the settlement, acceleration of the rate of consolidation, reducing the liquefaction potential and increasing the bearing capacity of foundations. The behavior of improved loose base-soil with gravel columns under shear loading and the shear stress-horizontal displacement curves got from large scale direct shear test are of great importance in understanding the performance of this method. In the present study, by performing 36 large-scale direct shear tests on sandy base-soil with different fine-content of zero to 30% in both not improved and improved with gravel columns, the effect of the presence of gravel columns in the loose soils were investigated. The results were used to predict the shear stress-horizontal displacement curve of these samples using support vector machines (SVM). Variables such as the non-plastic fine content of base-soil (FC), the area replacement ratio of the gravel column (Arr), the geotextile encasement and the normal stress on the sample were effective factors in the shear stress-horizontal displacement curve of the samples. The training and testing data of the model showed higher power of SVM compared to multilayer perceptron (MLP) neural network in predicting shear stress-horizontal displacement curve. After ensuring the accuracy of the model evaluation, by introducing different samples to the model, the effect of different variables on the maximum shear stress of the samples was investigated. The results showed that by adding a gravel column and increasing the Arr, the friction angle (ϕ) and cohesion (c) of the samples increase. This increase is less in base-soil with more FC, and in a proportion of the same Arr, with increasing FC, internal friction angle and cohesion decreases.

• Korea and Global Affairs
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• v.1 no.2
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• pp.33-84
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• 2017

This study deals with President Park Chung-hee's greed for dominance and oppression during the Yushin Regime in the 1970's and consists of case studies related to anti-democracy of the National Council for Unification Subject, illegality of President's emergency rule and oppression in the process of putting down Buma Uprising. The National Council for Unification Subject was an organization for presidential selection and institutionalized by the enactment of Yushin constitution. Emergency rule was carried into effect as a means to repressing college students and forces out of office for the president's long-term seizure of power. And Buma Uprising rose against violence in resistance to the Yushin regime and president Park Chung-hee's greed for dominance and oppression. These case analyses applied the aspects of causal relationship(birth and fall of Yushin Regime), legal system(Yushin constitution and president's emergency rule) and behavior(President Park's greed for dominance and oppression) for this study. The National Council for Unification Subject institutionalized through Yushin constitution and the Yushin regime formed by emergency rule enabled President Park to cling to long-term seizure of power by means of greed for dominance and oppression. After all, his failure to keep the spirit of the time and stepping stone for democratic constitutional government triggered Buma Uprising, a kind of anti-Establishment movement, and caused the fall of the Yushin regime.

• Strategy21
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• s.45
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• pp.33-59
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• 2019

There have many research papers to see China's evolution of maritime strategy and naval modernization in terms of its naval mind-set. However, this article focuses on assessing how China uses its all sorts of maritime strength to achieve 'a building maritime great power.' The aim of the article is to introduce a new perspective to this debate by analysing China's diversified ma maritime capabilities and a new way of implementation in maritime security strategy. In recent years, China has been developing not only unpredictable maritime military capabilities but also maritime supporting forces - Coast Guard and Maritime Militia. And recently China adopted up-to-date operational concept aimed at gaining military superiority in Asia-Pacific waters. By taking salami slicing strategy, gray zone strategy and cabbage strategy, China has been trying to exercise surpassing influences in regional maritime area, also in western Pacific region. This article provides a stepping stone to comprehend the aspect of China's recent maritime strategic actions, especially in Yellow Sea. In conclusion, this article suggests some policy recommendations for countering China's coercive maritime strategy. First, Korea should make sure a strategic concept of maritime security, instead of land warfare focused strategic concept. Second, it is needed to set up suitable naval forces for actively responding to neighbor nation's offensive actions.