• Journal of the military operations research society of Korea
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• v.34 no.2
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• pp.27-42
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• 2008

This study simulated the effect of the quantity flexibility contract(QFC) on the Korean military inventory system. The results shows that the QFC make the inventory system more efficient. For validity of this study, we assume the basic four demand patterns (increase, decrease, high variation and long seasonality) which are the exogenous variables of these simulation systems. We measured the difference of the traditional military inventory system's and new QFC system's performances. Under the all demand patterns, QFC models have little inventory than the traditional systems. We suggest, therefore, the military change the supply contract into QFC for decrease inventory and expect the results of this study applied to the company level.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.104-107
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• 2002

Traditional queueing analyses are very useful for designing a network's capacity and predicting there performances, however most of the predicted results from the queueing analyses are quite different from the realistic measured performance. And recent empirical studies on LAN, WAN and VBR traffic characteristics have indicated that the models used in the traditional Poisson assumption can't properly predict the real traffic properties due to under estimation of the long range dependence of network traffic and self-similarity. In this paper self-similar characteristics over statistical approaches and real time network traffic measurements are estimated. It is also shown that the self-similar traffic reflects network traffic characteristics by comparing source model.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.2099-2106
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• 2018

This study presents a novel approach of discriminative feature vectors based on manifold learning using nonlinear dimension reduction (DR) technique to improve loss function, and combine with the Adversarial examples to regularize the object function for image classification. The traditional convolutional neural networks (CNN) with many new regularization approach has been successfully used for image classification tasks, and it achieved good results, hence it costs a lot of Calculated spacing and timing. Significantly, distrinct from traditional CNN, we discriminate the feature vectors for objects without empirically-tuned parameter, these Discriminative features intend to remain the lower-dimensional relationship corresponding high-dimension manifold after projecting the image feature vectors from high-dimension to lower-dimension, and we optimize the constrains of the preserving local features based on manifold, which narrow the mapped feature information from the same class and push different class away. Using Adversarial examples, improved loss function with additional regularization term intends to boost the Robustness and generalization of neural network. experimental results indicate that the approach based on discriminative feature of manifold learning is not only valid, but also more efficient in image classification tasks. Furthermore, the proposed approach achieves competitive classification performances for three benchmark datasets : MNIST, CIFAR-10, SVHN.

• Journal of Communications and Networks
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• v.14 no.5
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• pp.481-486
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• 2012

Accurate and efficient estimation of the number of sources is critical for providing the parameter of targets in problems of array signal processing and blind source separation among other such problems. When conventional estimators work in unfavorable scenarios, e.g., at low signal-to-noise ratio (SNR), with a small number of snapshots, or for sources with a different strength, it is challenging to maintain good performance. In this paper, the detection limit of the minimum description length (MDL) estimator and the signal strength required for reliable detection are first discussed. Though a comparison, we analyze the reason that performances of classical estimators deteriorate completely in unfavorable scenarios. After discussing the limiting distribution of eigenvalues of the sample covariance matrix, we propose a new approach for estimating the number of sources which is based on a sequential hypothesis test. The new estimator performs better in unfavorable scenarios and is consistent in the traditional asymptotic sense. Finally, numerical evaluations indicate that the proposed estimator performs well when compared with other traditional estimators at low SNR and in the finite sample size case, especially when weak signals are superimposed on the strong signals.

• Journal of Power Electronics
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• v.19 no.6
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• pp.1527-1535
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• 2019

Because of the shortcomings of the PID controllers and traditional drive systems of permanent magnet synchronous motors (PMSMs), a PMSM passivity-based control (PBC) drive system based on a quasi-Z source matrix converter (QZMC) is proposed in this paper. The traditional matrix converter is a buck converter with a maximum voltage transmission ratio of only 0.866, which limits the performance of the driven motor. Therefore, in this paper a quasi-Z source circuit is added to the input side of the two-stage matrix converter (TSMC) and its working principle has also been verified. In addition, the controller of the speed loop and current loop in the conventional vector control of a PMSM is a PID controller. The PID controller has the problem since its parameters are difficult to adjust and its anti-interference capability is limited. As a result, a port controlled dissipative Hamiltonian model (PCHD) of a PMSM is established. Thereafter a passivity-based controller based on the interconnection and damping assignment (IDA) of a QZMC-PMSM is designed, and the stability of the equilibrium point is theoretically verified. Simulation and experimental results show that the designed PBC control system of a PMSM based on a QZMC can make the PMSM run stably at the rated speed. In addition, the system has strong robustness, as well as good dynamic and static performances.

• Journal of Distribution Science
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• v.22 no.1
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• pp.95-103
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• 2024

Purpose: Focusing on the complex supply chain operations beyond the simple dyadic relationship, this study evaluates the performance of the revenue sharing contract in three stage supply chain system. Research design, data, and methodology: The optimization model is developed to describe the supply chain system where one manufacturer, one wholesaler, and one retailer exist and pursue the maximum level of their own profits. In the numerical examples of the proposed supply chain model, two types of the revenue sharing contract, pairwise and spanning methods, are tested and their performances are compared with the traditional system. Results: The numerical analysis reveals that both types of the revenue sharing contract outperform the traditional system. All supply chain members can achieve the improved profits only when they determine the proper combination of revenue share ratios and price discount rates. Conclusions: This study finds out that both pairwise and spanning revenue sharing contracts can make the positive outcome that is acceptable to all members in three stage supply chain system. When the proper contract content is agreed among the supply chain members, the revenue sharing contract has the potential to be the practically feasible collaboration program for the multiple stage supply chain system.

• Journal of Practical Engineering Education
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• v.16 no.2
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• pp.251-257
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• 2024

After the pandemic, the world has brought about a society that connects to digital content faster. In the performing arts world, technology is also changing the production environment, content, and format of works. In addition, theatre and performances linked to digital media and virtual reality continue to be actively developed and increased. This paper first diagnoses how theater and acting education are meeting consumers(students) in a time when these changes progress rapidly. In the post-COVID-19 era, a crack began in the traditional method of education. We look at the existing problems of traditional education of theatre and acting in detail and look at the points of change from the changes in the virtual world and digital media environment. In conclusion, post-pandemic theater and acting education needs to shift to a consumer-centered paradigm.

• The Journal of the Acoustical Society of Korea
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• v.23 no.2
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• pp.146-161
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• 2004

There have been always some difficulties in target setting and conditioning of acoustic performances of the Korean traditional music hall due mainly to the lack of the information on the sound radiation characteristics of Korean musical sources. In this study, the radiation characteristics of four typical Korean traditional musical sources were investigated in precision and their usage was demonstrated: The selected musical sources were Gayageum (string), Daegeum (woodwind), Jango (drum), and Pansori Chang (vocal performance). Each sound source was located at the center of a semi-anechoic chamber and the directivity was determined by the measured sound pressure levels in every 10° angular position, for both vertical and horizontal directions. The directivity pattern of Gayageum varies from a uniform to a complex pattern having many side lobes with the increase of frequency. The main radiation of Daegeum is toward the upward direction. The directivity pattern of Jango is clearly a side-oriented one and the left direction intensity is sharper than its right side at low frequencies. For the Chang, the directivity pattern change from a uniform pattern to a frontally directed one as the frequency goes high. Measured directional and spectral characteristics of traditional Korean music sources were implemented into the computation of architectural acoustic measures for the Busan National Korean Traditional Music Hall which is under construction. Parameters such as RT, SPL, C80, IE, STI were calculated at two receiver positions by using a ray tracing technique. Significant differences in the acoustic measures at receiver positions were observed between the results in using the omni-directional source and the directional one. It is thought that the suggested source data and design method can be used as a basic reference in the future acoustic design of performance halls for the Korean traditional music.

• Convergence Security Journal
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• v.10 no.1
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• pp.41-48
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• 2010

Greedy protocols show good performance in Vehicular Ad-hoc Networks (VANETs) environment in general. But they make longer routes causing by surroundings or turn out routing failures in some cases when there are many traffic signals which generate empty streets temporary, or there is no merge roads after a road divide into two roads. When a node selects the next node simply using the distance to the destination node, the longer route is made by traditional greedy protocols in some cases and sometimes the route ends up routing failure. Most of traditional greedy protocols just take into account the distance to the destination to select a next node. Each node needs to consider not only the distance to the destination node but also the direction to the destination while routing a packet because of geographical environment. The proposed routing scheme considers both of the distance and the direction for forwarding packets to make a stable route. And the protocol can configure as the surrounding environment. We evaluate the performance of the protocol using two mobility models and network simulations. Most of network performances are improved rather than in compared with traditional greedy protocols.

• The Research Journal of the Costume Culture
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• v.27 no.4
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• pp.353-367
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• 2019

These days, costumes of Korean creative dancing performances have been changed to be modernized and to be out of traditional regulation, as the representation of the Korean styles were replaced by other props and art devices. In this article, we have applied the emotions expressed in Jin-Yi Hwang's sijos (Korean traditional poems), to Korean creative dancing costumes in modern style. chose three typical sijos from her six pieces, titled "Green mountain is like what I've meant", "To Byeokgyesoo in Cheongsan-ri" and "Dongjibam ginaginbam". In brief, Jin-Yi Hwang expressed her "everlasting love and emptiness", "temptative conciliation" and "eager waiting" these three sijos, respectively. The character of Jin-Yi Hwang was shown in many TV soap operas and films, and the costumes were either much modernized, and not accurately based on the sijos she had written. Thus, we designed, made flat sketched, and fabricated three Korean creative dancing costumes from the three sijos, listed. We tried to highlight the aesthetic impression and the activeness of the dancing costumes, using both traditional and modern Korean fabrics. Since Korean dance costumes had not yet been inspired from Jin-Yi Hwang's sijos, we discussed the importance of the fabric items, as well as the visual, auditory, and tactile characteristics of the costumes and dancers to emphasize Jin-Yi Hwang's expressed emotions.