• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.8
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• pp.396-400
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• 2005

This paper proposes the cost analysis on the energy efficient equipment when this equipment is participated in the demand-side bidding. Conventional demand-side bidding is exercised through load re-distribution. However if this load reduction is exercised by the use of high efficient equipment, its effect will be assumed to be more economical. This paper analyses this cost-benefit effect of high efficient equipment in the demand-side bidding.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6B
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• pp.559-567
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• 2009

Distributed Content Delivering Network (DCDN) will make use of the existing resources of the common Internet users in terms of storage space, bandwidth and Internet connectivity to create it. However DCDN has some limitations that are inefficient using of storage space, reliability and having special load balancing (LB) algorithm. So, this paper proposes Re-distribution based CDN (RDCDN) that overcomes the limitations of DCDN. RDCDN has the content re-distribution algorithm and separates surrogates to main surrogate and sub surrogates. Main surrogate can help service reliability be improved by storing all contents as back-up system. And content re-distribution algorithm also can help storage space be saved because all contents are not stored in every surrogate. Especially, when RDCwDN uses content re-distribution algorithm, it can work active load balancing function without extra LB algorithm like as DCDN. Results of simulation show that the proposed architecture can improve reliability and efficiency of storage space, and it also can offer the same performance as that of commercial CDN and DCDN.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.563-571
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• 1989

The load distribution factor in the perforated square plate under concentrated load acting at arbitrary points through elastic media are calculated. For the calculation the perforated plate was converted into an orthotropic plate using the method suggested by J.B. Mahoney. In the process of the calculation the angle support at each corners was equivalent to a point support having equivalent stiffness. The deflections for the calculation of the load distribution factor were obtained using auxiliary plate extended in both directions of the plate and compared with the results from ANSYS calculations. After showing the validity of the current method, the calculation of the load distribution factor was performed. The result showed that the load distribution factor at the periphery of the plate is larger than that of in the central locations. This load distribution factor could be used for re-distribution of the applied load in more accurate analysis of the plate as well as it can be used in the analysis of the elastic media as the load factor.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.350-353
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• 2000

This paper presents an algorithm for Optimal Reactive Power Dispatch(ORPD) problem based on genetic algorithm. Optimal reactive power dispatch is particularized to the minimization of transmission line losses by suitable selection of generator reactive power outputs and transformer tap settings. To reduce system loss and improve voltage profile, two methods, Loss Re-Distribution Algorithm (LRDA) and Voltage Dependent Load Model (VDLM), are applied to ORPD. The proposed methods have been evaluated on the IEEE 30 bus system. Each of results have been compared with result of load flow.

• Structural Engineering and Mechanics
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• v.70 no.1
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• pp.43-54
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• 2019

Due to various numerical problems, crack analysis of reinforced concrete members using the finite element method is confronting with substantial difficulties, rendering the prediction of crack patterns and crack widths a formidable task. The root cause is that the conventional analysis methods are not capable of tracking the crack sequence and accounting for the stress relief and re-distribution during cracking. To address this deficiency, the crack queuing algorithm has been proposed. Basically, at each load increment, iterations are carried out and within each iteration step, only the most critical concrete element is allowed to crack and the stress re-distribution is captured in subsequent iteration by re-formulating the cracked concrete element and re-analysing the whole concrete structure. To demonstrate the effectiveness of the crack queuing algorithm, crack analysis of concrete members tested in the literature is performed with and without the crack queuing algorithm incorporated.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.1
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• pp.111-117
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• 2007

This paper presents a new approach to evaluate reliability indices of electric distribution systems using genetic Algorithm (GA). The use of reliability evaluation is an important aspect of distribution system planning and operation to adjust the reliability level of each area. In this paper, the reliability model is based on the optimal load transforming problem to minimize load generated load point outage in each sub-section. This approach is one of the most difficult procedures and become combination problems. A new approach using GA was developed for this problem. GA is a general purpose optimization technique based on principles inspired from the biological evolution using metaphors of mechanisms such as natural selection, genetic recombination and survival of the fittest. Test results for the model system with 24 nodes 29 branches are reported in the paper.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.577-580
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• 2004

To overcome with large size noise source distribution network design difficulty in interferometric radiometer system, especially for sub-Y-type array, a new on-board calibration technique using noise re-radiation is proposed in this paper. The suggested calibration technique is using noise re-radiation effect of center antenna after noise source injection from matched load. This approach is especially proper to sub-Y-type array interferometric synthetic aperture radiometer in mm-wave frequency band. Compared with noise injection network of a conventional synthetic aperture radiometer, the system mass, volume, and hardware complexity is reduced and cost-effective. Only one internal noise source, matched load, is used for injection using noise re-radiation technique a small set of sub-Y receiver channels is calibrated. Detailed calibration scenario is discussed and simulation results about noise re­radiation effect are presented.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.5
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• pp.15-20
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• 2014

The wind industry grew in the first decade of the 21st century at rates consistently above 20% a year. For wind turbine, gearbox failure can be extremely costly in terms of repair costs, replacement parts, and in lost power production due to downtime. In this paper, gear tooth micro-modification for the high speed stage was used to compensate for the deformation of the teeth due to load and to ensure a proper meshing to achieve an optimized tooth contact pattern. The gearbox was firstly modeled in a software, and then the various combined tooth modification were presented, and the prediction of transmission under the loaded torque for the helical gear pair was investigated, the normal load distribution and root stress were also obtained and compared before and after tooth modification under one torque. The simulation results showed that the transmission error and normal load distribution under the load can be minimized by the appropriate tooth modification. It is a good approach where the simulated result is used to improve the design before the prototype is available for the test.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.4
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• pp.75-82
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• 2001

Static loadings on ship structure induced either by water pressure before service such as a tank test and ballasting or by cargo pressure during first laden voyage cause relatively much greater stress than dynamic loadings induced by wave. With these static pre-loadings, the initial residual stresses around welded joint, where fatigue strength is concerned(in most cases, where stress concentration occurs) are expected to be shaken-down in a great extent by the elasto-plastic deformation behavior of material. Therefore, it is more resonable to assess the fatigue strength of ship structure with S-N data which have taken into account the effect of shaken-down residual stresses(re-distributed stresses) on the fatigue strength. In this research work, the re-distribution of residual stresses by the tensile pre-loading is measured using an ordinary sectioning method for specimens of padding plate weldment. Fatigue tests are performed also to evaluate the fatigue strength of the both as-welded and pre-loaded specimens.

• Proceedings of the KIEE Conference
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• 2005.05b
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• pp.62-63
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• 2005

Recently, sectionalizing switches have been coming to be operated by remote control through the distribution SCADA system. However, the problem of determining the optimal switching sequence is a combinatorial optimization problem, and is quite difficult to solve, Hence, it is imperative to develop practically applicable solution algorithms create a new arbitral distribution system configuration from an initial configuration, and some of these algorithms do not show a load transfer sequence to reach the objective system.