• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.441-444
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• 1989

This correspondence presents a recursive estimation algorithm which, unlike conventional ones; updates the estimates only when a sufficient improvement can be obtained with a bounded noise assumption, the resulting sequence of estimates is a sequence of convex sets(ellipsoids) in the parameter space. For the cases studied, the algorithm use less than 20 percent of the. data to update, the estimate and still acquired good accuracy for spectral estimation.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.240-242
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• 1988

This paper proposes an improved ART (Algebraic Reconstruction technique) algorithm. This algorithm is an iterative one with iteration sequence criteria based on the discrepancy between measurement and pseudo-projection data. The simulation result using the proposed algorithm shows a significant improvement in convergency rate over the conventional ART algorithm.

• IE interfaces
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• v.14 no.2
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• pp.158-163
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• 2001

The paper describes disassemblability evaluation method using axiomatic approach. In recent industry, it is necessary to develope high recyclable environmental product due to green consumer and environmental regulations. Disassembly stage is prior to recycling. Disaassembly time data is determined previously in order to calculate the disassembly segments and disassembly sequence. In this paper the evaluation method of disassembly segment/sequence and disassembly time database are suggested. A case study of monitor product was showed.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10a
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• pp.340-342
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• 1999

시퀀스 데이터(sequence data)에서는 각 데이터 값보다는 전후 그들 사이의 변화추세 등이 더 큰 정보로 작용하는 것이 일반적이다. 본문에서는 시퀀스 데이터베이스를 대상으로 하여 주어진 시퀀스 패턴과 모양이 유사한 모든 부분시퀀스를 검색해 내는 새로운 방식을 제안한다. 본 방식에서는 시퀀스 데이터의 모양 추출을 위한 데이터 변환, 유사 모양 패턴 클러스터링, 새로운 유사도 계산 방식 등을 도입함으로써, 기존의 방식이 매우 제한적인 패턴만을 유사패턴으로 간주하던 것에 비하여, 패턴이 데이터축 혹은 타임축으로 각각 확대, 축소, 이동된 경우에도 유사패턴으로 검색이 가능하다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.22 no.3
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• pp.75-87
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• 1980

Most hydro]ogic phenomena are the complex and organic products of multiple causations like climatic and hydro-geological factors. A certain significant correlation on the run-off in river basin would be expected and foreseen in advance, and the effect of each these causual and associated factors (independant variables; present-month rainfall, previous-month run-off, evapotranspiration and relative humidity etc.) upon present-month run-off(dependent variable) may be determined by multiple regression analysis. Functions between independant and dependant variables should be treated repeatedly until satisfactory and optimal combination of independant variables can be obtained. Reliability of the estimated function should be tested according to the result of statistical criterion such as analysis of variance, coefficient of determination and significance-test of regression coefficients before first estimated multiple regression model in historical sequence is determined. But some error between observed and estimated run-off is still there. The error arises because the model used is an inadequate description of the system and because the data constituting the record represent only a sample from a population of monthly discharge observation, so that estimates of model parameter will be subject to sampling errors. Since this error which is a deviation from multiple regression plane cannot be explained by first estimated multiple regression equation, it can be considered as a random error governed by law of chance in nature. This unexplained variance by multiple regression equation can be solved by stochastic approach, that is, random error can be stochastically simulated by multiplying random normal variate to standard error of estimate. Finally hybrid model on estimation of monthly run-off in nonhistorical sequence can be determined by combining the determistic component of multiple regression equation and the stochastic component of random errors. Monthly run-off in Naju station in Yong-San river basin is estimated by multiple regression model and hybrid model. And some comparisons between observed and estimated run-off and between multiple regression model and already-existing estimation methods such as Gajiyama formula, tank model and Thomas-Fiering model are done. The results are as follows. (1) The optimal function to estimate monthly run-off in historical sequence is multiple linear regression equation in overall-month unit, that is; Qn=0.788Pn+0.130Qn-1-0.273En-0.1 About 85% of total variance of monthly runoff can be explained by multiple linear regression equation and its coefficient of determination (R2) is 0.843. This means we can estimate monthly runoff in historical sequence highly significantly with short data of observation by above mentioned equation. (2) The optimal function to estimate monthly runoff in nonhistorical sequence is hybrid model combined with multiple linear regression equation in overall-month unit and stochastic component, that is; Qn=0. 788Pn+0. l30Qn-1-0. 273En-0. 10+Sy.t The rest 15% of unexplained variance of monthly runoff can be explained by addition of stochastic process and a bit more reliable results of statistical characteristics of monthly runoff in non-historical sequence are derived. This estimated monthly runoff in non-historical sequence shows up the extraordinary value (maximum, minimum value) which is not appeared in the observed runoff as a random component. (3) "Frequency best fit coefficient" (R2f) of multiple linear regression equation is 0.847 which is the same value as Gaijyama's one. This implies that multiple linear regression equation and Gajiyama formula are theoretically rather reasonable functions.

• Journal of the Korea Convergence Society
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• v.12 no.11
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• pp.109-117
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• 2021

Recently, the use of speech-based interfaces is increasing as a means for human-computer interaction (HCI). Accordingly, interest in post-processors for correcting errors in speech recognition results is also increasing. However, a lot of human-labor is required for data construction. in order to manufacture a sequence to sequence (S2S) based speech recognition post-processor. To this end, to alleviate the limitations of the existing construction methodology, a new data construction method called Back TranScription (BTS) was proposed. BTS refers to a technology that combines TTS and STT technology to create a pseudo parallel corpus. This methodology eliminates the role of a phonetic transcriptor and can automatically generate vast amounts of training data, saving the cost. This paper verified through experiments that data should be constructed in consideration of text style and domain rather than constructing data without any criteria by extending the existing BTS research.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.7
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• pp.498-509
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• 1988

A BF(breadth-first) linear quadtree as a new data structure for image data is suggested, which enables us to compress the image data efficiently and to make operations of the compressed data easily. It is a list of path names for black nodes as the linear quadtree is. The path name for each black node of a BF linear quadtree is represented as a sequence of path codes from the root node to itself, whereas that of linear quadtree as a sequence of path codes from the root node to itself and fill characters for cut-offed path from it to any n-level node which corresponds to a pixel of an image. The BF linear quadtree provides a more efficent compression ratio than the linear quadtree does, because the former does not require redundant characters, fill characters, for the cut-offed paths. Several operations for image processing can be also implemented on this hierarchical structure efficiently, because it is composed of only the black nodes ad the linear quadtree is . In this paper, algorithms for several operations on the BF linear quadtree are defined and analyzed. Experimental results for forur image data are also given and discussed.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.10
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• pp.156-165
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• 1998

In this paper, the hybrid algorithm for the scene change detection of MPEG-based compressed video data is proposed. There have been two methods to detect scene changes of video data compressed using algorithms such as MPEG or motion-JPEG: analyzing the compressed data directly, and analyzing from the retrieved data. The former has the advantage of taking less time, while the latter can obtain detail results at the expense of time and memory. Thus by combining each algorithm we detect cuts from compressed sequence, retrieve data for some selected region, and detect gradual scene changes. Simulation results verify the superiorities of the proposed algorithm in analyzing time and accuracy.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.11
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• pp.1-11
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• 1998

We present somple block methods for blind maximal ratio combining (MRC) based on a maximum likelihood (ML) principle and finite alphabet properties (FAP) inherent in digital communication systems. The methods can provide accurate estimates of channel parameters even with a small subset of data, thus realizing nearly perfect combining. The channel parameters of diversity branches and the data sequence are estimated simultaneously by using an alternating projection technique. Two different methods, that is, (1) Joint combining and data sequence estimation(JC-DSE) method and (2) Pre-combining and blind phase estimation (PC-BPE) method are presented. Efficient initiallization schemes that can assure the convergence to the global optimum are also presented. Simulation results demonstrate the performance of two methods on the symbol error rate (SER) and the estimated accuracy of the channel parameters.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.3
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• pp.276-282
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• 2003

OFDM is effective for the high speed data transmission. However, the nonlinear distortion is a serious problem because of the high PAPR due to many subcarriers. The conventional SLM selects the OFDM signal with the lowest PAPR. In this method, OFDM data can be correctly recovered only if the side information about the phase sequence is transmitted to receiver. This paper proposes a new method of side information insertion into the conventional SLM and reduces the computational complexity by adaptive method. Performances are compared in case that three kinds of phase sequences are used for phase rotation factor. The adaptive SLM method has the same PAPR reduction as the conventional SLM method. The required BER can be guaranteed by the proposed method. When subcarrier number N=32, computational complexity is reduced to 48 %, 72 % and 51 % for the branch number U=4, 8 and 16, respectively.