• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1341-1345
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• 2005

Sequential Monte Carlo techniques are a set of powerful and versatile simulation-based methods to perform optimal state estimation in nonlinear non-Gaussian state-space models. We can use Monte Carlo particle filters adaptively, i.e. so that they simultaneously estimate the parameters and the signal. However, Sequential Monte Carlo techniques require the use of special panicle filtering techniques which suffer from several drawbacks. We consider here an alternative approach combining particle filtering and Sequential Hybrid Monte Carlo. We give some examples of applications in fisheries(luespotted mud hopper data).

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.292-294
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• 2001

문서 클러스터링은 정보검색 시스템에서 검색과정의 효율성을 향상시키기 위해서 많이 사용된다. 기존의 K-means 클러스터링과 같은 거리-기반 접근 방법은 거리에 대한 척도를 정해야 하는 문제가 있고, 또한 전체 자질 공간에서 지역적 특성에 민감하기 때문에 문서 내에 노이즈가 존재할 경우 만족스러운 결과를 내지 못할 수 있다. 그리고 기본적으로 문서 데이터는 희소성(sparseness)을 가기 때문에 정규 분포를 가정한 mixture 모델을 적용하기도 어려움이 있다. 본 논문에서는 Helmoholtz machine에 의한 문서 클러스터링 방법을 제안한다. 제안되는 방법에서는 하나의 문서를 어떤 내재적인 요인(factor)들의 다양한 결합에 의한 결과로 가정하는데, 이 때의 요인은 주제어 집합 또는 적어도 의미적으로 유사한 단어들의 집합이다. 그리고 기본적으로 Helmholtz machine은 이진 데이터를 다루는데, 텍스트 문서에 나타나는 단어들의 빈도를 고려하기 위해 수정된 Helmholtz machine을 제시한다. TREC-8 adhoe 데이터와 20 Newsgroup 문서 집합에 대한 클러스터링 실험 결과, 제안된 방법이 K-means 알고리즘에 비해 우수한 성능을 보였으며 주제어 추출을 통해 문서 집합의 전체 내용 파악을 용이하게 하는 특성이 있었다.

• Proceedings of the Safety Management and Science Conference
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• 2008.11a
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• pp.599-610
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• 2008

It is an important and urgent issue to improve process capability in quality control. Process capability refers to the uniformity of the process. The variability in the process is a measure of the uniformity of output. A simple, quantitative way to express process capability, the degree of variability from target in specification is defined by process capability index(PCI). Almost process capability indices are defined under normal distribution. However, these indices can not be applied to the process of non-normal distribution including reliability. We investigate current research on the process of non-normal distribution, and advanced method and technology for developing more reliable and efficient PCI. Finally we suggest the perspective for future study.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.4
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• pp.46-54
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• 1995

This paper presents a simple method for measurenemt of roughness of ground surfaces. The present method utilizes fluxes of scattered lights condensed through lenses aligned along the specular direction. A theoretical analysis is preformed for the purpose of investigating the possibility of the method as well as determining the experimental condition. Experiments are also performed to show the effectiveness and robustness of the proposed method. The theoretical and experimental results show that the proposed method is simple enouth to implement and has a potential to identify a wide range of roughness of ground surfaces.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.4
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• pp.223-231
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• 2013

This paper presents a time-domain Gauss-Newton full-waveform inversion method for the material profile reconstruction in heterogeneous semi-infinite solid media. To implement the inverse problem in a finite computational domain, perfectly-matchedlayers( PMLs) are introduced as wave-absorbing boundaries within which the domain's wave velocity profile is to be reconstructed. The inverse problem is formulated in a partial-differential-equations(PDE)-constrained optimization framework, where a least-squares misfit between measured and calculated surface responses is minimized under the constraint of PML-endowed wave equations. A Gauss-Newton-Krylov optimization algorithm is utilized to iteratively update the unknown wave velocity profile with the aid of a specialized regularization scheme. Through a series of one-dimensional examples, the solution of the Gauss-Newton inversion was close enough to the target profile, and showed superior convergence behavior with reduced wall-clock time of implementation compared to a conventional inversion using Fletcher-Reeves optimization algorithm.

• Korean Journal of Plant Tissue Culture
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• v.27 no.2
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• pp.77-82
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• 2000

This study was conducted to determine the inheritance of the ability of callus formation and plant regeneration in seed cultures of rice. The culturabilities of three Japonica rices,'Chucheongbyeo', 'Nagdongbyeo', and 'Daeribbyeo 1', were higher than those of Tongil type cultivars, 'Milyang 23' and 'Samgangbyeo 'The frequency for callus growth in F₂ populations of the three crosses, 'Milyang 23/Chucheongbyeo', 'Milyang 23/Daeribbyeo 1', and' Samgangbyeo/Nagdongbyeo', revealed a nearly normal distribution. The broad-sense heritability estimated from the ability of callus formation in the crosses were ranged from 83.8% to 90.1%. The frequency distribution of plant regenerability in F₂ population of 'Milyang 23/Daeribbyeo 1' showed a continuous variation. But the segregation mode of plant regenerability from seed-derived callus in the F₂ progenies of 'Milyang 23/Chucheongbyeo' and 'Samgangbyeo/Nagdongbyeo' appeared to fit the expected 3 : 1 ratio for the high and low regenerability. These results suggest that the high plant regenerability of 'Chucheongbyeo' and 'Nagdongbyeo' was regulated by a single dominant gene.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.1
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• pp.14-19
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• 1990

This paper describes on the characteristics of the acoustic echoes from the scattering layers by the aggregation of marine organisms which was measured by using a 50kHz echo sounder on board of the training ship SAEBADA belong to National Fisheries University of Pusan during the summer, 1989 in the East China Sea. A data acquisition system was used to record digitally the envelope of the echoes and the frequency distribution of echo amplitudes on the whole water column was examined as a function of time during the sunrise and sunset periods. Acoustic data showed that the abundance distribution of marine organisms according to depth in the servery area changed with time and that the organisms were most active during the twilight of morning, and the echo strength on the water column or scattering layer was also strongest during this time. Additional results of this survey suggest that other interest, such as the relationship between environmental conditions and biomass depth distribution, could be also investigated in hydroacoustic method.

• Journal of the Korean Geotechnical Society
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• v.26 no.5
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• pp.57-64
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• 2010

Kriging techniques have been used to estimate the spatial distribution of soil layers and soil properties in the geotechnical engineering area. Since the selected kriging technique may provide different values of estimation, the selection of method is important in the geotechnical estimation. In this paper, the spatial distribution of the thickness of consolidation layer of Songdo International City is estimated using simple, ordinary, and universal kriging techniques, and the reliability of estimated results is analyzed. It is shown that the consolidation layer thickness estimated by the simple kriging technique is larger than those by other kriging techniques when the location of estimation is far from the locations where the measured data exist. In this case, the reliability of the simple kriging technique is observed to be lower than those of other techniques. Universal kriging gives a negative value for thickness of consolidation layer in some locations away from the data. It is concluded that the ordinary kriging is the most optimized estimation technique because the reliability of ordinary kriging technique is higher than those of other ones and the consolidation layer thickness estimated by the ordinary kriging locates within the reasonable range.

• Smart Media Journal
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• v.11 no.7
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• pp.76-84
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• 2022

In Korea, where rice is the staple food, there are many cases in which the nutritional composition of food is different at the same weight, even though the same ingredients are used and the food or food name is the same. The cause is closely related to the moisture content of the food according to the cooking method and cooking process. In order to design a diet tailored to individual health and supply accurate calories and nutrients, a method of expressing food data that is not affected by the cooking process or cooking method is required. Usually, the same ingredients or foods show a lot of deviation from the nutritional components presented in the standard food database due to the difference in moisture content. For this reason, there are problems that increase the complexity of the food ingredient database and the difficulty in using it. As a method to improve these problems, we would like to propose a food data expression method based on dry weight. As an example of this, the characteristics of rice as a food material and changes in major nutritional components according to the change in moisture of various rice-processed foods made from rice were considered. In addition, as an example of how to normalize food data through this, the dry weight-based nutrition label of rice was presented.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.2
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• pp.83-94
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• 2010

The objective of this study was to determine the best probability distributions of annual, seasonal and monthly precipitation in Korea. Data observed at 32 stations in Korea were analyzed using the L-moment ratio diagram and the average weighted distance (AWD) to identify the best probability distributions of each precipitation. The probability distribution was best represented by 3-parameter Weibull distribution (W3) for the annual precipitation, 3-parameter lognormal distribution (LN3) for spring and autumn seasons, and generalized extreme value distribution (GEV) for summer and winter seasons. The best probability distribution models for monthly precipitation were LN3 for January, W3 for February and July, 2-parameter Weibull distribution (W2) for March, generalized Pareto distribution (GPA) for April, September, October and November, GEV for May and June, and log-Pearson type III (LP3) for August and December. However, from the goodness-of-fit test for the best probability distributions of the best fit, GPA for April, September, October and November, and LN3 for January showed considerably high reject rates due to computational errors in estimation of the probability distribution parameters and relatively higher AWD values. Meanwhile, analyses using data from 55 stations including additional 23 stations indicated insignificant differences to those using original data. Further studies using more long-term data are needed to identify more optimal probability distributions for each precipitation.