• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.10
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• pp.1845-1851
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• 2007

Background noise and room reverberation are two causes of degradation in speech in listening situations. Many algorithms developed to enhance reverberant speech. In this paper we propose a dereverberation method for enhancement of speech using modified the linear prediction(LP) residual in reverberant room condition. The proposed dereberberation method based on the fact that the signification excitation of the vocal tract system takes place at the instant of glottal closure in voiced speech. Our method used delay information form each sensor, and we need reverberant signals from 3 sensors. We obtain a new LP residual signal using modified IP residual combination which derived form weighting of the LP residual and the Hilbert transform of LP residual. The nature of the coherently added Hilbert envelop has several large amplitude spikes because of the effects of noise and reverberation. This residual of the clean speech is used to excite the time-varying all-pole filter to obtain the enhanced speech. We achieved simulation of proposed algorithm for performance analysis in reverberation environment. The proposed algorithm improves substantially the quality of reverberant speech.

• Journal of Digestive Cancer Research
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• v.1 no.1
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• pp.43-47
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• 2013

There have been very few reports related to pancreatic cancer developing in the remnant pancreas after a resection for pancreatic cancer. We report two cases of repeated pancreatectomy for second primary pancreatic cancer. A 58-year-old man with a 2.3 cm sized low attenuated pancreatic tail mass on abdomen CT scan, received a distal pancreatectomy (adenosquamous carcinoma, stage IIB) and adjuvant chemoradiotherapy. A follow-up abdomen CT scan revealed a 2.0 cm sized pancreatic head mass in the remnant pancreas at 35 months after the distal pancreatectomy. He received a pancreaticoduodenectomy and diagnosed as ductal adenocarcinoma (stage IIA). Another 62-year-old female was declared pancreatic head mass on a regular health examination. An abdomen CT scan revealed a 3.6 cm sized mixed solid and cystic mass. She received a pylorus-preserving pancreaticoduodenectomy (ductal adenocarcinoma, stage IB) and adjuvant chemoradiation therapy. At 20 months after the resection, a 1.8 cm sized ill-defined low attenuated mass developing in the tail of remnant pancreas was detected on a follow-up abdomen CT scan. The patient received a distal pancreatectomy and diagnosed as ductal adenocarcinoma (stage IIA).

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.2
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• pp.25-36
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• 2007

We researched the change of astigmatism power when the fixation point moved from far distance to near distance. Astigmatism power was measured by using both eyes open-view auto-refractometer. We divided the ages between 5 and 67 years old into 12 groups with 1,598 healthy eyes(male-698 eyes and female-900 eyes) without eyes problems and experiences of eyes operations. The mean power in far astigmatism showed that with-the-rule of the total astigmatism: -0.79D, with-the-rule of the corneal astigmatism: -1.07D and against-the-rule of the residual astigmatism : -0.79D were found most respectively. The correlation between cornea astigmatism and total astigmatism was y=0.7493 x + 0.5661 r=0.6510, residual astigmatism and total astigmatism was y=0.248 x - 0.5926 r=0.2598 and corneal astigmatism and residual astigmatism was y=-0.4439 x - 0.1813 r=-0.5551 in the far distance. The mean power in near astigmatism showed that with-the-rule of total astigmatism : -0.92D, with-the-rule of corneal astigmatism : -1.12D, against-the-rule of residual astigmatism : -0.87D were found most respectively. In the near distance, The correlation between corneal astigmatism and total astigmatism was y=0.6872 x + 0.5934 r=0.6204, residual astigmatism and total astigmatism was y=0.303 x - 0.6066 r=0.3165, corneal astigmatism and residual astigmatism was y=-0.46 x - 0.0626 r=-0.5322. When the fixation point moved far distance to near distance, the differences of power according to the type of astigmatism were total astigmatism: $-0.07D{\pm}0.44D$, corneal astigmatism: $-0.04D{\pm}0.54D$ residual astigmatism:$0.01D{\pm}0.53D$. Most of astigmatism refractive power was increased except for oblique-the -astigmatism. When the fixation point moved far distance to near distance, the change of astigmatism refractive power showed total astigmatism: 540 eyes(33.7%), corneal astigmatism: 638 eyes(39.9%), residual: 841 eyes(52.6%).

• Journal of the Korean Data and Information Science Society
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• v.5 no.2
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• pp.45-57
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• 1994

이 연구에서는 Hjort(1991)에의해 제안된 누적위험률함수의 비모수적 추정량을 이용하여 무한인 구간까지 정의된 평균잔여수명함수의 추정량을 제안하고 제안된 추정량의 일치성과 점근적 정규성을 밝히고, 모의실험을 통하여 다른 추정량들과 비교하고자 한다.

• The korean journal of orthodontics
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• v.26 no.5 s.58
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• pp.613-622
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• 1996

The purposes of this study were to evaluate and compare the frequency of ceramic bracket fracture, frequency of enamel fracture, bond fracture site, adhesive remnant index after mechanical and electrothermal debracketing, to evaluate effectiveness of high and low speed rotary instrument and ultrasonic instrument during residual adhesive remnants removal, and to measure resin film surface(percentage) using by image analyser(Leco 300). Bond fracture site, bracket fracture, and enamel surface damage were examined by scanning electron microscope. The following results were obained : 1. In the mechanical debracketing group, the bond failed predominantly at enamel-adhesive interface with the bulk of adhesive remaining on bracket base. 2. In the eletrothermal debracketing group, the bond failed predominantly at adhesive-bracket interface with the bulk of adhesive remaining on enamel surface. 3. The most effectiveness of residual resin removal was obtained by means of the resin polishing bur and the order of scratch formation was the procedure using tungsten carbide bur, ultrasonic scaler, sof-lex disc, and polishing bur. 4. The order of the resin film surface percentage was ultrasonic scaler, tungsten carbide bur, sof-lex disc, and resin polishing bur.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.323-334
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• 2011

In this study, we performed the residual geoid modeling using the FFT and LSC methods in context of application of R-R (Remove and Restore) technique as a general technique for gravimetric geoid model in order to propose the effective way of geoid determination in Korea. For this, a number of data compiled for residual geoid modeling by the multi-band spherical FFT method with Stoke's formula and LSC method as known as statistical method. The geometric geoidal heights obtained from 503 GPS/Levelling data were used for inducing the various elements and proper computation process which should be considered for improving the accuracy of residual geoid modeling. Finally, we statistically compared the results of residual geoid heights between FFT and LSC methods and reviewed then the proper way of residual geoid modeling to the region of Korea. As the results of comparison, LSC method is not suitable for residual geoid modeling in Korea due to the noise and lack of gravity observations and the effects of local characteristics, while FFT method by applying Stokes' integral with proper cap size and modified kernel which provides the better accuracy of residual geoid heights up to 10 cm more than those of LSC method.

• Journal of the Korean Institute of Gas
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• v.25 no.5
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• pp.30-36
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• 2021

Residual life assessment of reformer tubes of mod HP steel used in the refinery and petrochemical industry were investigated by quantitative metallographic evaluation method. Area fractions of precipitated carbides were measured by using surface replication and its relationship with the remaining life of the tube was investigated. The microstructures of the virgin and other tubes were examined using optical microscopy (OM) for service periods of 1.8, 6.0, 7.2, 8.5, 9.7, and 16.2 years at 950 ℃ and the area fractions of the precipitates were measured by image analysis using ImageJ software. As the area fraction of the precipitates increased, the residual life was decreased accordingly. The results showed that the LMP was the highest in the virgin and the LMP decreased as the service time increased and the residual life decreased. A regressional equation showing the relation between the area fraction of carbides and LMP was experimentally derived. The obtained relationship can be used with the surface replication method for on-site residual life assessment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.10
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• pp.814-822
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• 2018

This paper proposes a guidance law for missiles with control time constraint. Because the proposed guidance law is based on a time-to-go polynomial, it has a generalized form. Also, acceleration of the proposed law converges to zero at the end of the control time, which reduces the sensitivity to the time-to-go estimation error and can increase the flight stability when the separation of the missile appears. A prediction method of the time-to-go is proposed for implementing the proposed law, and the possibility of application to the midcourse and terminal guidance phases is dealt with for exoatmospheric interception. The characteristics and performance of the proposed law are analyzed throughout various simulations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.1997-2003
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• 2010

Mean Residual Life (MRL) function plays a very important role in the area of engineering, medical science, survival studies, social sciences, and many other fields. Specially, in the reliability study of technical systems, the MRL estimation of a component is very important because the sudden stop of a system brings a serious problem. So, many simulation studies of MRL estimation have been done considering various situation variables. In this paper, four estimators of MRL are proposed under random censoring and their performances re compared through bias and Mean Square Error (MSE) by Monte Carlo simulation.

• Korean Journal of Construction Engineering and Management
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• v.3 no.1 s.9
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• pp.107-114
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• 2002

Recently, a few major construction companies in Korea have a growing interests to the risk management system, and they are trying to apply it to their construction projects. However, the existing methodologies to be applied to the foreign public projects are not proper to the construction environments due to its adaptabilities, that has one time process and heavily depends on personal judgement. The purpose of this paper is to propose a risk response process in consideration of the residual risks, which would be more adaptable and practical in the construction environment, overcoming the current obstacles to be mentioned above. This process has systematic repeat process until the residual risks go down to the risk thresholds based on the efficiency of specific response strategy.