• Journal of Soil and Groundwater Environment
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• v.6 no.3
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• pp.53-59
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• 2001

There is a lot of method to manage the insanitary landfill but vertical cutoff walls have been widespreadly used and were installed into the subsurface to act as a barrier to horizontal groundwater flow, The stabilized material such as specialized cement or mixed soil with additives has been generally applied for the materials of the deep soil mixing barrier in korea. The amount of the stabilized material is dependent on the field conditions, because the mixing ratio of the material and the field soil should achieve a requirement in the coefficient of permeability, lower than 1.0$\times$$10^{7}$cm/sec. This study determined the quantity and optimized function ratio of the stabilized material in the formation process of the mixed barrier that was added with stabilized material on the field soil classified into SW-SC under USCS (Unified Soil Classification System). After that the fly ash and lime were selected as an additives an that could improve the function of the stabilized material and then the method to improve the functional progress in the usage of putting into the stabilized material as an appropriate ratio was studied and reviewed. The author used the flexible-wall permeameter for measuring the permeability and unconfined compressive strength tester for compressive strength, and in the view of environmental engineering the absorption test of heavy metals and leaching test regulated by Korean Waste Management Act were performed. As the results, the suitable mixing ratio of the stabilized material in the deep soil mixing barrier was determined as 13 percent. To make workability easy, the ratio of stabilized material and water was proven to be 1 : 1.5. With the results, the range of the portion of the additives(fly ash : lime= 70 : 30) was proven to be 20-40% for improving the function of the stabilized material, lowering of permeability. In heavy metal absorption assessment of the mixing barrier system with the additives, the result of heavy metal absorption was proved to be almost same with the case of the original stabilized material; high removal efficiency of heavy metals. In addition, the leaching concentration of heavy metals from the leaching test for the environmental hazard assessment showed lower than the regulated criteria.

• Proceedings of the Acoustical Society of Korea Conference
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• 1995.06a
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• pp.76-80
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• 1995

Differential pulse code modulation 구조의 Line spectrum pairs 양자화기에 높은 차수 LSP 파라미터 값은 낮은 차수 LSP 파라미터 값보다 커야한다는 LSP 파라미터의 순서화 특징을 이용하여 양자화하는 방법을 제시한다. 31 비트/프레임에서 1 dB 이하의 스펙트럴 왜곡을 갖는 명료한 음질을 보였다. 또한 LSP 주파수의 순서화 특성은 벡터-스칼라 결합 양자화기에 적용하였다. 벡터-스칼라 결합 양자화기에서는 26비트/프레임에서 명료한 음질을 보였다. 새로운 LSP 양자화 방법들은 전송에러 발생시 성능을 시험하고, 전송 에러에 강인하도록 프레임간 예측을 위해 Moving Average 예측기를 사용한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.635-639
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• 2004

댐과 같은 구조물의 설계시 큰 강우량에 내한 분포함수의 적합성을 놀일 필요가 있다. 이에 대해 Wang (1997a and b)은 큰 설계량에 내한 적합성을 놀이기 위해 LH 모멘트와 고차 PWM(higher Probability Weighted Moments)방법을 제안하였다. 따라서 본 연구에서는 우리나라의 자 지역별로 대표적인 4개 지점의 일 강우량 자료를 사용하여 제안된 고차 PWM 방법의 적용성을 살펴보았다. 그 과정으로 가장 낮은 차수인 일반적인 PWM 방법과 더 높은 차수의 PWM 방법을 이용하여, GEV(Generalized Extreme Value) 분포와 Gumbel 분포에 대한 매개변수를 추정한 후 이 추정치를 확률지에 실측치와 함께 도시하여 결과를 비교하였다. 그리고 PPCC(Probability Plot Correlation Coefficient) 적합도 검정결과를 통해 추정된 매개변수의 적합성을 확인하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.653-656
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• 2008

The main purpose of this research was to enhance the durability in both the design and construction of dams. Especially, in case of rockfill dams, the durability of face slab concrete in a concrete-faced rockfill dam(CFRD) is achieved by optimizing the fly ash replacement for cement and application of blended fiber. The effect on durability and thermal property corresponding to the increasing replacement of fly ash and application of blended fiber was evaluated, and the optimum value of fly ash replacement and blended fiber application was recommended. The results show that 15% of fly ash replacement and 0.9kg/m3 of blended fiber application was found to be an optimum level and demonstrated excellent performance in durability and thermal property.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1309-1314
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• 2012

The SAMED filter is introduced as a wide class of multi-stage filters which encompass linear FIR and nonlinear order statistic filters. The output of SAMED filter is linear combination of sub-median outputs. In this paper, optimal SAMED filter is designed for images corrupted by various noise, and performance is analogized. The experimental result shows that the efficiency of each order of SAMED filters is depends on type of noise. It is shown that low order filters are effective in Gaussian environments but high order filters are effective in impulsive case. This result may be used to follow-up research on successive SAMED filters.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5A
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• pp.593-601
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• 2000

In a multi-bandwidth CDMA system, the performance of multiple order selection combining rake receivers are analyzed according to the spreading bandwidth of the system and the delay spread of the Rayleigh fading channel. The results for various channel environments indicate a tradeoff between total received signal energy and multipath fading immunity. Increasing the occupied bandwidth of the system(wide-bandwidth spreading) gives better performance for small delay spread environments, while gathering more energy(narrow-bandwidth spreading)gives better performance for large delay spread environments. It is shown that the performance difference between low and high order selection combining grows larger as the spreading bandwidth increases. It is also noted that performance degrades by increasing the bandwidth above a certain point and the optimum spreading bandwidth for each channel environment decreases as the delay spread of the channel increases.

• Journal of Korea Soil Environment Society
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• v.4 no.2
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• pp.149-161
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• 1999

In this study, to examine the applicability of the lime sludge as a landfill liner, 1) the geoechnical characteristics of sludge, 2) the characteristics of migrations of contaminants, and 3) the characteristic of leaching in the batch leaching test are investigated As a result, the hydraulic conductivity(K) of the lime sludge was found out to have 10 times lower hydraulic conductivity than the maximum allowable hydraulic conductivity of the liner Retardations of heavy metals(Cu, Pb) were found out to be higher than that of organic(phenol) due to the high pH(>11.0) of 4he lime sludge. As a result of the leaching test. the concentrations of Pb and Cu were found to be close to allowable limitation, so that they need to be kept in constant watch.

• Journal of Biomedical Engineering Research
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• v.20 no.6
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• pp.591-599
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• 1999

연구개에 결함이 있는 사람의 발음은 부적절한 비음이 섞이게 되어 과비음성 비음이 되어 연구개를 복원해주는 시술을 하게 되는데, 과비음성 비음을 정량적으로 측정할 수있다면 시술 결과를 객관화 할 수 있게 된다. 현재 임상적으로 사용되고 있는 방법들은 관혈적이거나 고가의 장비를 필요로 한다. 본 논문에서는 비음의 특징인 스펙트럼에서 zero 의 존재와 비강에 의한 포만트의 존재 사실, 그리고 선형 예측 모델을 이용하여 마이크로폰과 사운드 카드가 장착된 PC로 구현할 수 있는 새로운 과비음성 비음 추정 알고리즘을 제안하였다. 음성 신호의 스펙트럼에 zero가 존재하는 경우, 낮은 차수(order)의 선형 예측 모델이 그 음성을 발음한 성도 시스템에 정확히 적용되지 않는다는 점을 이용하여, 같은 음성에 대한 높은 차수의 선형 예측 모델과의 차이를 이용해서 과비음성의 정량화를 시도했다. 본 논문에서는 제안된 알고리즘은 기존의 Teager Operator를 이용한 알고리즘에 비해서 Nasonmeter 의 측정결과와 더 높은 통계적 상관관계를 보여주었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.10A
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• pp.1782-1793
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• 2001

터보부호 심벌비트들을 서로 다른 부호율로 반복부호화한 뒤 여러 부채널로 나란히 보내는 터보 부호화 여러반송파 직접수열 부호분할 다중접속 시스템을 제안한다. 레일리 감쇄채널에서 신호대잡음비가 높을 때에는 이 시스템의 성능 한계를 얻었고, 신호대잡음비가 낮아 한계를 적용할 수 없을 때에는 모의실험에서 성능을 살펴보았다. 신호대잡음비가 낮을 때 성능 손실이 조금 있지만 홀짝 검사(parity check) 심벌에 다양성 차수를 크게 주어 오류 마루를 (error floor) 낮출 수 있음을 보였다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.1
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• pp.125-133
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• 2009

Security of biometric data is particularly important as the compromise of the data will be permanent. To protect the biometric data, we need to store it in a non.invertible transformed version. Thus, even if the transformed version is compromised, its valid biometric data are securely remained. Fuzzy vault mechanism was proposed to provide cryptographic secure protection of critical data(e.g., encryption key) with the fingerprint data in a way that only the authorized user can access the critical data by providing the valid fingerprint. However, all the previous results cannot operate on the fingerprint image with a few minutiae, because they use fixed degree of the polynomial without considering the number of fingerprint minutiae. To solve this problem, we use adaptive degree of polynomial considering the number of minutiae. Also, we apply multiple polynomials to operate the fingerprint with a few minutiae. Based on the experimental results, we confirm that the proposed approach can enhance the security level and verification accuracy.