• The Journal of Society for e-Business Studies
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• v.5 no.2
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• pp.61-79
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• 2000

For CALS environment, sharing information among business processes within the enterprise and between enterprises have been increased through common database. To support integrated data environment, data of the local legacy system must coincide with data of the global system to guarantee data integrity and transparency. This study is concerned with the implementation of this distributed database system under CALS environment. Based on existing IDEF methods, we developed a modified method which newly includes concepts of the enterprise structure, the integration of legacy databases, the distribution of data, and the distributed applications .

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.371-373
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• 2001

In this paper, we present 2-step load cycle for daily load curve of up to and including 100kVA distribution transformer in domestic. Daily load patterns are classified by two methods dependent upon possession information. In case we possess daily load profiles make use of K-mean algorithm and in case we have not daily load profiles, make use of customer information of KEPCO. As the parameters of the load pattern classification, we use are daily load profiles and customer information of each distribution transformers. Data management system is used for NT oracle. We can present peak load magnitude, initial load magnitude and peak load duration for daily load patterns by 2-step load cycle for daily load curve of up to and including 100kVA distribution transformer in domestic. We think that this paper contributes to enhancing the distribution transformer overload criterion.

• Journal of the Korean institute of surface engineering
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• v.24 no.3
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• pp.125-136
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• 1991

a mathematical model is presented to describe the current distribution on a rotaing disk electrode under the galvanostatic pulse conlitions. A numerical technique by finite difference method to the transient convective diffusion equation, coordinate transformation and separation of variables to Laplace equation, and an iterative algorithm to solve the above equations simtltaneously with approximate boundary conditions were developed. An experimental investigated based on copper deposition in a copper sulfate-sulfuric acid system was performed and satisfactory agreement was obtained between expermental and theoretical current distribution. The current distribution of copper deposition is secondary current distribution within the experimental conditions. Dimensionless variables, N and J as well as Wagner number were used to determine the criteria for the uniformity of current distribution.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.370-377
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• 2002

Generally, the system of calculation for the multi-path ultrasonic flow meters can be divided into two methods by how to get the mean velocity, namely, weighting and direct method. Weighting-method derive the mean velocity through modeling in theoretical velocity profile. Direct-method derive the mean velocity though actual flow distribution. The system of calculation varies with maker's transducer configuration and integration method. Each system has merits and demerits. This paper describes the system of integration that calculates line velocity over cross-section of the circular pipe. Flow rate mr discussed in this paper is a difference between theoretical flow rate and integrated flow rate according to values of Reynolds number in symmetric flow field or theoretical flow rate and integrated flow rate according to rotated model in asymmetric flow field.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.9
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• pp.952-960
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• 2008

Fan noise prediction method is presented for air conditioning, automobile and electronic cooling system applications where fan acts as an internal equipment having very complicated flow interaction with other various system components. The internal flow paths and distribution in the fan-applied systems such as computer or air conditioner are analyzed by using the FNM(flow network modeling). Fan noise prediction method comprises two models for the discrete frequency noise due to rotating steady aerodynamic lift and blade interaction and for the broadband noise due to turbulent boundary layer and wake vortex shedding. Based on the fan operation point predicted from the FNM analysis results and fan design parameters, the present far noise model predicts overall sound pressure level and spectrum. The predictions for the flow distribution, the fan operation and the noise level in air cooling system by the present method are well agreed with 3-D CFD and actual noise test results.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1407-1418
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• 2018

Novel mechanism of customized adequacy formulation is proposed in order to enhance micro grids system reliability. The mechanism accounts for 2-levles of load curtailment, and is mainly based on probabilistic load profile and hybrid Distributed Generation (DG) units modeling. The two load curtailments are needed in order to ensure adequate technical constraints at steady state condition during islanding mode of operation. The effectiveness of the proposed formulation has been verified using system independent analytical expressions for the evaluation of both reliability and Expected Energy Not Served (EENS) indices. The evaluation has examined the impact of different penetration levels of Hybrid DG Units in case study islands. Results show the enhancement of the overall distribution system reliability and the recommended conditions for successful islanding mode of operation.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1107-1114
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• 2017

In this paper, a miniaturized distribution line was experimentally made. The smart grid distribution system was modeled by analyzing the distribution system, and a miniaturized micro three phase distribution system recloser was designed. The micro recloser was designed as a sensor part, a main part and a relay part, and the main part was designed to cut off the fault current by determining the fault from the input current based on the DSP. Finally, based on the results of the modeling, the micro three phase power distribution line and the micro three phase recloser were experimentally fabricated, and the basic making technology of the miniaturized micro smart grid was obtained through the making process.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.5
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• pp.431-438
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• 2000

The major irreversibilities in absorption chillers are associated with the transfer of heat into and out from the machine and irreversible process inside the machine. By modeling only external irreversibilities(endo-reversible), a model was formulated to predict the ideal performance of a single-effect absorption chiller. Its actual performance including both external and internal irreversibilities was calculated with a in-house simulation program. The optimization of heat transfer area distribution was performed for both endo-reversible cycle and actual cycle. The equation of endo-reversible modeling was found to give about 2times higher cooling capacity than the simulation program. At optimal distribution, it was found that heat transfer area of the evaporator was about 30% of total area, that of the generator was 20%, and the rest 50% was for the absorber and condenser. The system COP for endo-reversible cycle was slightly higher than that for actual cycle. In the case of LiBr-water single-effect absorption chiller, the maximum cooling capacity was obtained near the condition that LMTD is same at all heat exchangers.

• The Journal of the Convergence on Culture Technology
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• v.3 no.1
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• pp.43-48
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• 2017

We are confirmed to the variation of the transfer condition and the functional penetration by the permitted conversion energy on the skin. The given conversion energy is consist of the flow level of penetration control and go to the processing transfer in the skin that is to create the modeling for algorithm. The energy level of control processing was achieved effectively modeling system that was the composition of auto and local control level in the epidermis-dermis layer. Their penetration pulse control system was consisted of conversion energy with reference of fixing situation and recreation of designed apparatus for the energy control function that was converted to capacity by the size, form and combination. Also, the system was shown accurately distribution of conversion at the depth of skin correction. Therefore, conversion modeling was established effectively to separate the division parts for conversion system. We will be possible to progress the improvement effectiveness of the skin and to consist of the continuous penetration control system for functional energy on the skin.

• Fire Science and Engineering
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• v.18 no.1
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• pp.42-48
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• 2004

The deterministic modeling techniques like Zone model and Field model are mainly used for thermal distribution and smoke flow at fire case in multi use facilities. While Zone model analyse fire simulation by dividing spaces by 2 section, the Field model dividing many cells. However, the difficultly follows to prove efficiency between the two models when it applys. Therefore new modeling development is required which in closes to real situation by verify number algorithm and related data for fire modeling. The paper analyses the efficiency of two different fire modeling at interior spaces of multiplex cinema theater. It is found that the zone model for average distribution and the field model for detail space phenomenon are relevant to apply. Also, Filed model is useful to the result that fire analysis and position of detector and review for smoke control system.