• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.3
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• pp.59-68
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• 2005

The rainfall-runoff potential of Jangseong reservoir watershed was studied based on SCS (Soil Conservation Service, which is now the NRCS, Natural Resources Conservation Service, USDA) runoff curve number (CN) technique. Precipitation and reservoir operation data had been collected. The rainfall-runoff pairs from the watershed for ten years was estimated using reservoir water balance analysis using reservoir operation records. The maximum retention, S, for each storm event from rainfall-runoff pair was estimated for selected storm events. The estimated S values were arranged in descending order, then its probability distribution was determined as log-normal distribution, and associated CNs were found about probability levels of Pr=0.1, 0.5, and 0.9, respectively. A subwatershed that has the similar portions of land use categories to the whole watershed of Jangseong reservoir was selected and hydrologic monitoring was conducted. CNs for subwatershed were determined using observed data. CNs determined from observed rainfall-runoff data and reservoir water balance analysis were compared to the suggested CNs by the method of SCS-NEH4. The $CN_{II}$ measured and estimated from water balance analysis in this study were 78.0 and 78.1, respectively. However, the $CN_{II}$, which was determined based on hydrologic soil group, land use, was 67.2 indicating that actual runoff potential of Jangseong reservoir watershed is higher than that evaluated by SCS-NEH4 method. The results showed that watershed runoff potential for large scale agricultural reservoirs needs to be examined for efficient management of water resources and flood prevention.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.1
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• pp.75-79
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• 2007

The cathode design is one of the most important parts in order to enhance the performance of fuel cells. A 3-D model of the porous oxygen reducing cathode with perforated current collectors is analysed for the enhanced design in fuel cells. Simulation is performed using equations of electric potential balance, momentum balance, and mass balance. The gas concentrations are quite large and are significantly affected by the reactions that take place. The weight fraction of oxygen, velocity field for the gas phase, and local overvoltage are illustrated in the porous reactive cathode layer. The current density is also analysed and the result shows the distribution and variation are stated in a wide range. It is found that the rate of reaction and the current production is higher beneath the orifice, and decreases as the distance to the gas inlet increases. The significance of the results is discussed in the viewpoint of the mass transportation phenomena, which is inferred that the mass transport of reactants dictates the efficiency of the electrode in this design and at these conditions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.688-691
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• 2004

We have studied the possibility of global noise reduction by the sound power control through selection of distribution and impedance of absorptive materials. It is necessary to investigate the relation between the global sound energy in the field and the total sound power radiated by sources. In the previous work (1,2), the authors presented a useful design method to change boundary condition that can be useful to reduce noise in acoustically small enclosures. The possibility of total acoustic potential energy reduction by acoustic source power control is examined in an acoustically small cavity. Using acoustic energy balance equation, the relation between global noise control performance and absorptive material's arrangement/impedance is deduced. Numerical simulation is performed to interpret its physical meaning in terms of absorbent's distribution and impedance.

• Journal of the Korean Wood Science and Technology
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• v.31 no.1
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• pp.61-70
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• 2003

The size distribution of the free water paths between earlywood and latewood for six species in the heartwood of softwoods was estimated from the amount of dehydrated free water under various centrifugal fields, such as 2,200, 3,300, 4,800 and 6,900 rpm. The centrifugal method is based on the concept that water movement occurs by the balance of centrifugal force and water potential by meniscus. Water stops where the pressure differential is zero. In the centrifugal field, only two factors affect water movement in wood, that is, centrifugal force and water potential. Also, the water permeability was evaluated from the relationship between the water saturation ratio after the centrifugal treatment and the measure of water potential in specimen. The results showed that Cryptpmeria japonica had clear peaks at 0.70 ㎛ in earlywood and at 0.50 ㎛ in latewood. Tsuga sieboldii and Larix kaemferi had peaks at 0.50 and 0.30 ㎛ in both earlywood and latewood, respectively. Abies firma showed peaks at 0.70 ㎛ in earlywood and at 0.30 ㎛ in latewood. The water permeability of earlywood was higer than that of latewood for all softwoods except Pseudotsuga menziesii.

• Nuclear Engineering and Technology
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• v.49 no.5
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• pp.905-913
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• 2017

Advanced reactor designs often feature longer operating cycles between refueling and new concepts of operation beyond traditional baseload electricity production. Owing to this increased complexity, traditional proportional-integral control may not be sufficient across all potential operating regimes. The prototypical advanced reactor (PAR) design features two independent reactor modules, each connected to a single dedicated steam generator that feeds a common balance of plant for electricity generation and process heat applications. In the current research, the PAR is expected to operate in a load-following manner to produce electricity to meet grid demand over a 24-hour period. Over the operational lifetime of the PAR system, primary and intermediate sodium pumps are expected to degrade in performance. The independent operation of the two reactor modules in the PAR may allow the system to continue operating under degraded pump performance by shifting the power production between reactor modules in order to meet overall load demands. This paper proposes a Takagi-Sugeno (T-S) fuzzy logic-based power distribution system. Two T-S fuzzy power distribution controllers have been designed and tested. Simulation shows that the devised T-S fuzzy controllers provide improved performance over traditional controls during daily load-following operation under different levels of pump degradation.

• Journal of Distribution Science
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• v.14 no.7
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• pp.101-114
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• 2016

Purpose - The aim of this study is to investigate the benefit-sharing activities. They affect contract renewal intention between franchisers and franchisees that are linked through a contract with the intention of building their relationship from the level based on dynamic trust. This study will show a new approach on qualitative growth and consolidation of competitive power and may well be able to suggest practical ways to strengthen directions in the field of franchise industries. Research design, data, and methodology - In this study, based on literature review, we separated logistical-supporting activities and non-logistical-supporting activities from benefit-sharing activities. We modeled how benefit-sharing activities influence contract renewal intention of franchisees by dynamic trust. In particular, considering the possibility of trading concepts and characteristics of trust between providers opportunistic behaviors was defined as variables, depending on the situation and dynamic characters reveal their relationship trust concept. That is, dynamic trust having the possibility of changing depending on opportunistic risks and interdependencies by Lewis & Weigert(1985, 2012) was classified into transitional-based trust, calculated based trust, relational-based trust and balance-based on trust. The total of 104 samples from domestic franchisees being with franchisees were collected by using a structural composed questionnaire. Results - The results are as following. Benefit-sharing activities in logistical supporting activities appeared to affect the multidimensional concept of transitional trust, calculated based on trust, relationship-based trust and balance based on trust dynamic trust with all-defined impact. Non-logistical supporting activities appeared to affect significantly the positive (+) to the dynamic trust concept except transitional trust. Lewis & Weigert(1985; 2012) have proposed a dynamic confidence calculated from relations within-based trust relationship based on trust appears to affect the significant positive (+) to the balance-based confidence transactions confidence mechanism of the system side in the verified relationship. Finally, a relationship based on trust and confidence in the balance based on the Influence of dynamic renewed confidence showed significantly affect the positive(+). In particular, the balance based trust showed the acts as a mediating factors between relational trust and confidence and renew calculated. Conclusion - From the above these results, the significance from this study is as following. First, the proposed activity is to share and validate the approach by identifying the potential in the relationship from the contract with building dynamic trust, and one of the ways from the franchise headquarters and affiliated merchants mutual growth through win-win cooperation in sharing activities. Next, the dynamic segmentation confidence to suggest the possibility can be broken down over the validity and reliability test for each concept. In addition, by identifying the relationship between the dynamic level of confidence granular multi-dimensional concept, to determine the level of trust with a dynamic relationship between risk and interdependencies can be possible in franchise industries. In order to maintain and develop their mutual relationship, franchise industries should propose confidence-building steps to promote their quality improvement.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.8
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• pp.668-674
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• 2004

The possibility of global noise reduction by the sound power control through selection of distribution and impedance of absorptive materials is discussed. It is necessary to investigate the relation between the global sound energy in the field and the total sound power radiated by sources. In the previous work,$^{(1.2)}$ the authors presented a useful design method to change boundary condition that can be useful to reduce noise in acoustically small enclosures. Changing boundary condition Is related to not only enclosure’s geometrical shape but also acoustical treatment on walls for example, attaching of impedance patches (ex: absorptive material). In many practical situations, we often meet situation to change acoustical treatment on walls. The possibility of total acoustic potential energy(globa1 noise) reduction by acoustic source power control is examined in an acoustically small cavity Using acoustic energy balance equation, the relation between global noise control performance and absorptive material’s arrangement/impedance is deduced. Numerical simulation is performed to interpret its physical meaning in terms of absorbent’s distribution and impedance.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.3
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• pp.315-325
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• 2019

The paper aims to explore the factors affecting potential users of international bank cards in Vietnam. With milestones treaties being signed CPTPP and EVFTA, Vietnam is now exposing itself to the international open environment. Bank card market is at the core of this wind of change, and that is the reason for us to research the intention to use international bank cards. Given that the decision to choose international bank cards could either be the switch from domestic cards or adopting a brand new card, we develop some specific constructs to reflect that consideration, specifically PE and PD, asides from traditional constructs used in TPB and TAM frameworks. The analysis work is conducted using PLS-SEM approach. Our findings reveals that most of our proposed hypotheses are supported, in which SN plays the most important direct role to INT, while total effect of PU on INT is similar to that of SN. The newly introduced PD negatively and significantly impacts INT, and PE also has a positive impact on INT. The findings suggest that overall, it is important for bank card issuers to have a balance approach to the market, with focus on increasing usefulness and reducing potential disadvantages of international bank cards.

• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.25-31
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• 2011

The purpose of power system maintenance is to prevent equipment failure. The maintenance strategy should be designed to balance costs and benefits because frequent maintenance increases cost while infrequent maintenance can also be costly due to electricity outages. This paper proposes maintenance modeling of a power distribution system using reliability centered maintenance (RCM). The proposed method includes comprehensive equipment modeling and impact analysis to evaluate the effect of equipment faults. The problem of finding the optimum maintenance strategy is formulated in terms of dynamic programming. The applied power system is based on the RBTS Bus 2 model, and the results demonstrate the potential for designing a maintenance strategy using the proposed model.

• Transactions on Electrical and Electronic Materials
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• v.1 no.4
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• pp.16-19
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• 2000

Power transistors to be used in Power Integrated Circuits(PIC) are required to have low on resistance, fast switching speed, and high breakdown voltage. The lateral IGBTs(LIGBTs)are promising power devices for high voltage PIC applications, because of its superior device characteristics. In this paper, dual cathode LIGBT(DCIGBT) for high voltage is presented. We have verified the effectiveness of high blocking voltage in the new device by using two dimensional devices simulator. We have analyzed the forward blocking characteristics , the latch up performance and turn off characteristics of the proposed structure. Specially, we have focused forward blocking of LIGBT. The forward blocking voltage of conventional LIGBT and the proposed LIGBT are 120V and 165V, respectively. . The forward blocking characteristics of the proposed LIGBT is better than that of the conventional LIGBT. This forward blocking comparison exhibits a 1.5 times improvement in the proposed LIGBT.