• Proceedings of the IEEK Conference
• /
• 1999.06a
• /
• pp.130-133
• /
• 1999

In the view point of further reducing the inter-symbol interferences studied in our previous paper 〔1〕, a quadrature pair of wavelet-based filter banks that are composed of a pair of cosine and sine modulated filter banks is applied to MC-CDMA transmultiplexing. For that fact, the symbol duration gets twice longer than the one in , 〔1〕, the interference effects due to channel overlapping and Doppler spread can be effectively alleviated while increasing the channel utilization efficiency. Moreover, the well-known wavelet properties are exploited to design the prototype filter in such a way to maintain the size of sidelobes much smaller than those of the FFT, the interference reduction effect can be further obtained. To verify the behavior of our proposed quadrature filter bank based MC-CDMA system, the reverse-link bit error rates with respect to SNR under Rayleigh fading and additive white Gaussian noise channel environments are computed. The results show an improved system performance over the conventional MC-CDMA.

• Proceedings of the IEEK Conference
• /
• 1999.06a
• /
• pp.601-604
• /
• 1999

We propose a new hierarchical motion estimator architecture that supports the advanced prediction mode of recent low bit-rate video coders such as H.263 and MPEG-4. In the proposed VLSI architecture, a basic searching unit (BSU) is commonly utilized for all hierarchical levels to make a systematic and small sized motion estimator. Since the memory bank of the proposed architecture provides scheduled data flow for calculating 8$\times$8 block-based sum of absolute difference (SAD), both a macroblock-based motion vector (MV) and four block-based MVs are simultaneously obtained for each macroblock in the advanced prediction mode. The proposed motion estimator gives similar coding performance compared with full search block matching algorithm (FSBMA) while achieving small size and satisfying the advanced prediction mode.

• Communications for Statistical Applications and Methods
• /
• v.27 no.3
• /
• pp.327-347
• /
• 2020

We consider a credit portfolio with highly skewed exposures. In the portfolio, small number of obligors have very high exposures compared to the others. For the Bernoulli mixture model with highly skewed exposures, we propose a new importance sampling scheme to estimate the tail loss probability over a threshold and the corresponding expected shortfall. We stratify the sample space of the default events into two subsets. One consists of the events that the obligors with heavy exposures default simultaneously. We expect that typical tail loss events belong to the set. In our proposed scheme, the tail loss probability and the expected shortfall corresponding to this type of events are estimated by a conditional Monte Carlo, which results in variance reduction. We analyze the properties of the proposed scheme mathematically. In numerical study, the performance of the proposed scheme is compared with an existing importance sampling method.

• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.137-142
• /
• 1998

This paper describes a simple vector control scheme for the wound rotor type induction motors(WRIM) without the additional speed sensor in order to remove the external resistor bank which is usually adapted for the WRIM speed control. The motor angular speed is obtained indirectly from the slip angular speed is obtained indirectly from the slip angular speed and the slip angular speed is estimated by detecting the rotor currents only. Because the motor parameters are not included in the estimation algorithm, the proposed algorithm is free from the variation of the motor parameters and the robust sensorless vector control can be achieved. The performance of the proposed scheme is verified through the digital simulation.

• 한국생물공학회:학술대회논문집
• /
• 2002.04a
• /
• pp.386-389
• /
• 2002

Antagonistic Bacillus sp. #16 to phytopathogenic fungi were selected based on the growth rate, inhibition rate and surface tension reduction. Based on the 16S rRNA sequences, Bacillus sp. #16 is closely related to the B. subtilis DSM10. In the pot test, Bacillus sp. #16 show the most effective growth inhibition against damping-off disease of cucumber seeding.

• Journal of Power Electronics
• /
• v.12 no.3
• /
• pp.458-467
• /
• 2012

Single phase converters suffer from ripple power pulsating at twice the line frequency. The ripple power is usually absorbed by a bulky capacitor bank and/or a dedicative LC resonant link, resulting in a low power density and a high cost. An alternative solution is using a dc link active power filter (APF) to direct the pulsating power into another energy-storage component. The main dc link filter capacitor can then be reduced substantially. Based on a mainstream dc APF topology, this paper proposed a new control strategy incorporating both dual-loop control and repetitive control. The circuit parameter design is also re-examined from a control point of view. The proposed APF scheme has better control performance, and is more suited for high power applications since it works in CCM and with a low switching frequency.

• The Journal of Asian Finance, Economics and Business
• /
• v.3 no.2
• /
• pp.21-31
• /
• 2016

Although the microfinance sector in Bangladesh is mainly driven by Non-Governmental-Organizations (NGOs), there are other types of Microfinance Institutions (MFIs) that also provide financial services to the poor. Despite the criticism of microfinance programs, the current poverty situation in Bangladesh still requires such programs for consistently battling poverty. Hence, the aim of this paper is to profile the microfinance sector based on their legal status and investigate any possible differences (if any) between them in various aspects. After a thorough investigation of the sector, it was found that around 33 million of the clients are being served by the mainstream MFIs (NGO and Grameen Bank) while another 10-15 million clients are served by other types of MFIs (financial cooperatives, credit unions, various ministries etc.), accounting for the one-third of the total population in Bangladesh. While the mainstream MFIs basically works with poor, other categories of MFIs are concerned with relatively wealthy clients. Looking into the financial performance and social intermediation of the MFIs, the NGO-MFIs performed better than other types of MFIs in the sector.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.63
• /
• pp.261-282
• /
• 2014

A Silk Road was connecting East and West with trade route. The role From the ancient, Silk Road is situated in the Central Asia such as Kazakhstan, thus logistics sector was important more than others. This theme is the study of the Export Competitiveness of Korea-Kazakhstan trade. This paper analyses between Korea and Kazakhstan's trade used by TSI(trade specification index), IITI(intra-industry trade index) and CTBI(contribution to trade balance index). The World Bank is already addressing Kazakhstan's logistics inefficiencies is the lowest tier. Thus, Kazakhstan governments should encourage efficiency in Logistic parts. And more Korea is supporting to decrease Logistic cost.

• Journal of the Korean Statistical Society
• /
• v.27 no.3
• /
• pp.305-318
• /
• 1998

Smoothing tests based on an L$_2$ error between a truncated courier series estimator and a true function have shown good powers for a wide class of alternatives, These tests have the same form of the Neyman smooth test whose performance depends on the selected order, a basis, the farm of estimators. We construct flexible data driven Neyman smooth tests by changing a basis, combining model selection criteria and different series estimators. A simulation study shows that the generalized Neyman smooth test with the best basis provides good power for a wider class of alternatives compared with other data driven Neyman smooth tests based on a fixed form of estimator, a fixed basis and a fixed criterion.

• Journal of Engineering Education Research
• /
• v.16 no.4
• /
• pp.15-20
• /
• 2013

The result of the English test for freshmen showed wide difference in the ability of students, which means the graded class is strongly required. This paper describes the case study about the graded English class that was carried out for the freshman. Every freshman must take an English placement test from problems bank and were classified according to the result of the test. In order to resolve the dissatisfaction of the high level students, the statutes of my university for credit were modified. In order to analyze the effect of the graded class, evaluation test using similar problems was carried out at the end of the semester. The effect of the graded class was analyzed by using the paired samples t-test method and there was a meaningful performance improvement at the average score. Additional improvements in the method of classification and credit granted were made by analyzing the results of the evaluation test and survey.