• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.280-285
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• 2005

At present, there are several problems related with sand mat which is used as a way to accelerate consolidation settlement, act like an underground drainage layer and increase trafficability simultaneously. First of all, the unbalance oft he demand and supply of sand is the one of the biggest problems, which makes not only price advance of sand but also delays a term of total construction work. Secondly, the damage of ecosystem and scenery is triggered by thoughtless sand dredging or mining. So, the need that the sand for sand mat should be replaced with a new environmental friendly material has been increased. Fiber mat may be one of the proper materials that suits the need. Therefore, we intended to compare the drainage properties of sand mat with those of fiber mat by experimental model tests. On the basis of the test results, fiber mat took shorter period of consolidation than sand mat and it's amount of settlement showed a little bit bigger than the other. In conclusion, the substitutability of fiber mat for sand mat could be placed highly in view of drainage efficiency. Furthermore, when Fiber mat is used, it has an advantage that spoil soil of the construction site or nearby site can be used for the purpose of increasing trafficability in addition to a role of drainage layer.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.8
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• pp.1057-1067
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• 2010

Vibration and noise analysis as well as strength of gear teeth, gear profile design are considered in order to develop the multi-gear train devices of synchro system for the guns of a warship. A new approach to the critical speed calculation of practical industrial multi-mesh geared system is presented. A transfer matrix model based on Hibner's branch method is developed and the natural properties of the branched rotor system are calculated with using the ${\lambda}$-matrix formulation. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors and the transmitted errors of the gearing are considered, shows that, at theoperating speed, there are not the critical speed.

• Journal of Biomedical Engineering Research
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• v.29 no.5
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• pp.408-413
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• 2008

Human body has a complete left and right symmetry structure, and the left and right balance by Yin and Yang. When the balance is broken, the left and right Meridian becomes abnormal condition. Acupuncture is a kind of therapy to recover from energy unbalance of the left and right Meridian to a new balance condition. In the study, we observed the electric potential along the stomach meridian (ST) in order to verify the energy consensus phenomenon by transportation of bio-energy between operator and subject during acupuncture. The acupuncture effects on opposite meridian site were investigated by comparing the electric potentials between the right and left ST sites. Meridian electrical potentials (MEPs) between operator and subject were simultaneously generated during the acupuncture and the polarity of MEPs was opposite. The results might imply the bio-energy transportation between operator and subject. In addition, we observed three different patterns of MEPs on both ST sites which might represent the condition of the related meridians because meridians in the body are organically interconnected.

• Journal of Fisheries and Marine Sciences Education
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• v.17 no.3
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• pp.340-360
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• 2005

Fishery resource rents(i.e. windfall gains or excess profit), which tend to lead a variety of important economic, social, political problems, have been a fundamental cause of unbalance between fishery resource use and management. Thus, there may exist several sorts of optimal level of resource utilization such as economic maximum sustainable yield, biological maximum sustainable yield, social optimum production, socio-political optimum yield, etc. The fishery resource use level seems to a large extent to be determined by the characteristics of fishermen's rent seeking structure. As well known, fishery resources as common properties have a characteristic of being difficult to establish private property rights. Therefore, their use rights are controlled by the permit and/or the license system. As a result, absolute or differential rents are formed by the changes in institutional arrangements. Rent problems are often transformed into serious socio-political issues when the rent in a given industry is much higher to a socially unacceptable extent than the average of other industries. However, individual fishermen or fishermen's groups tend to behave aggressively to change the existing fishery institutions towards maximizing fishery rents. These rent-seeking behaviors often tend to nullify fishery management schemes. The larger is the relative rent difference between fisheries and other industries, the more aggressive tend to be the rent-seeking behaviors in fisheries.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.11 s.104
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• pp.1262-1267
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• 2005

The paper presents the identification of dynamic property of a rotor system with a squeeze film damper (SFD) using magnetic fluid. An electromagnet Is installed in the inner damper of the SFD. The magnetic fluid is well known as a functional fluid. Its rheological property can be changed by controlling the applied current to the fluid and the fluid can be used as lubricant. Basically, the proposed SFD has the characteristics of a conventional SFD without an applied current, while the damping and stiffness Properties change according to the variation of the applied electric current. Therefore, when the applied current is changed, the whirling vibration of the rotor system can be effectively reduced. The clustering-based hybrid evolutionary algorithm (CHEA) is used to identify linear stiffness and damping coefficients of the SFD based on measured unbalance responses.

• Journal of the Korea Computer Industry Society
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• v.3 no.12
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• pp.1651-1658
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• 2002

Recently power cable used generally in Korea, because installation is very simple and it has high stability. It confirms to the requirements of IEEE std. 404-1993 by factory testing, but many problems of insulated cable systems are caused by internal defects of the joint part which have to be mounted ensile. Especially, fault rates are arise from impurities or voids. A suitable solution for a monitoring of power cable during the after-laying test and service is partial discharge detection. The artificial defects between cable joint(EPR) and insulator(XLPE) interface are considered in this research to investigating the partial discharge characteristics. ${\varphi}$-q-n properties were detected using data acquisition system and Maximum charge($q_{max}$), repetition rate(${\={n}$), average charge(${\={q}$), Unbalance rate of ${\={n}$ and ${\={q}$ are calculated in order to analysis partial discharge properties quantitatively from this statistic value.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.6
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• pp.87-94
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• 2017

Hot stamping processes are possible for tensile strength 1.4 GPa but the strength reduction is appeared from the cooling performance unbalance. And the strength of roll forming process is below than that of hot stamping process owing to using the steel which is lower strength of boron steel. In this study, We provide roll forming process asssisted high-frequency induction heating to solve the problem of conventional one. The experiments were carried out at under various sill side part conditions: high-frequency induction heating conditions of 15, 18, 21, 24, 27 and 30 kW. The high-frequency induction heating temperature was checked with Infrared camera and the sill side parts of mechanical properties and microstructure were measured. The heating temperature of high frequency induction was measured to max $850^{\circ}C$ under the coil power of 30 kW. The tensile strength was 1.5 GPa and hardness was 490 Hv. The martensite structure was discovered under coil power of 30 kW. The weight of steel material sill side having thickness 1.5 mm and the boron steel sill side having thickness 1.2 mm were compared to weight effect. The boron steel sill side reduced 11.5% compared to steel. Consequently, manufacturing process of 1.5 giga-grade's sill side part was successfully realized by the roll forming assisted high-frequency induction heating methods.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.8
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• pp.752-760
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• 2011

In tilting pad bearing design process, the selection of the proper configuration type of either a load-between-pad(LBP) or load-on-pad(LOP) as well as preload and pivot offset conditions is to be carefully considered. Also the bearing needs to be designed in order to be suited for the rotor-bearing system and operating condition. In this paper, it is observed that the dynamic characteristics in a five pad tilting pad bearing for the LBP and the LOP configurations are influenced by the variation of preload and pivot offset. In this context, rotor dynamic analysis of the 5 MW industrial gas turbine supported by the tilting pad bearing at the front and roller bearing at the rear is carried out based on the dynamic coefficients of the tilting pad bearing investigated. The result shows that two rigid body critical modes experience various changes according to the influence of the tilting pad bearing uniquely applied to one side of this machine. Mainly, the second critical speed, the rigid body mode of conical shape with high whirling in the tilting pad bearing, is significantly changed by preload and pivot offset regardless of the LBP and LOP configurations. And, the first critical mode, the rigid body mode of conical shape with high whirling in the roller bearing, is sensitively affected by preload applied to the LOP configuration and by its asymmetric dynamic properties.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.425-432
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• 2011

In tilting pad bearing design process, the selection of the proper configuration type of either a Load-Between-Pad (LBP) or Load-On-Pad (LOP) as well as preload and pivot offset conditions is to be carefully considered. Also the bearing needs to be designed in order to be suited for the rotor-bearing system and operating condition. In this paper, it is observed that the dynamic characteristics in a 5 pad tilting pad bearing for the LBP and the LOP configurations are influenced by the variation of preload and pivot offset. In this context, rotor dynamic analysis of the 5MW industrial gas turbine supported by the tilting pad bearing at the front and roller bearing at the rear is carried out based on the dynamic coefficients of the tilting pad bearing investigated. The result shows that two rigid body critical modes experience various changes according to the influence of the tilting pad bearing uniquely applied to one side of this machine. Mainly, the second critical speed, the rigid body mode of conical shape with high whirling in the tilting pad bearing, is significantly changed by preload and pivot offset regardless of the LBP and LOP configurations. And, the first critical mode, the rigid body mode of conical shape with high whirling in the roller bearing, is sensitively affected by preload applied to the LOP configuration and by the its asymmetric dynamic properties.

• Journal of the Korean Society for Library and Information Science
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• v.48 no.4
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• pp.297-322
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• 2014

The purpose of this study is to analyse the meaning and lexical morpheme of author keywords of humanities, social sciences, and art and sport in the Korea Ciation Index (KCI) and to propose a conceptual taxonomy of the author keywords. Four top-level concept categories such as 'Substance, Abstraction, General/Common, and Object' are replaced by seven more concrete categories such as 'object, action/function, property, theory/method, format/framework, general/common, and Instance'. In the middle and lower-level concept categories, the hierarchical structure is simplified and the unbalance of term distribution is reduced by creating, subdivision, integration, elimination, and movement of the categories. The result of the test based on the STNet shows that the replaced taxonomy of concept categories has the effects of making the term allocation more balanced and properties of terms more detailed.