• The Journal of the Acoustical Society of Korea
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• 제24권3E호
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• pp.87-89
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• 2005

The acoustical sources of intake and exhaust systems in fluid machines are often characterized by the source impedance and strength using linear frequency-domain modeling. In the case of the sources which are nonlinear and time-variant, however, the source parameters were sometimes incorrectly obtained. In this paper, the source model and direct measurement technique are modified in order to evaluate the effect due to nonlinear and periodically time-varying source character as well as the linear property of the reflectivity of in-duct fluid machine source. With a priori known kinematical information of the source, the types of nonlinear time-variant terms can be presumed by a simple physical model, in which there is practically no restriction on the form of the model. The concept of source impedance can be extendable by introducing the linear frequency response function for each nonlinear or time-variant input. Extending the conventional method and adapting the reverse MISO technique, it is possible to develop a direct method that can deal with the nonlinear time-variant source parameters. The proposed direct method has a novel feature that there is no restriction on the probability or spectral natures of the excited sound pressure data. The present method is verified by the simulated measurements for simplified fluid machines. It is thought that the proposed method would be useful in predicting the insertion loss or the radiated sound level from intake or exhaust systems.

• 천문학회보
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• 제35권2호
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• pp.70.1-70.1
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• 2010

최근에 새롭게 발견된 초신성잔해 G353.6-0.7은 $\gamma$-ray source로부터 발견된 최초의 초신성 잔해이다. 이 초신성잔해의 중앙에서는 밝은 X-ray compact source, XMMU J173203.3-344518이 발견되었다. 우리는 위 X-ray compact source 근처에 IR source, IRAS 17287-3443이 매우 가까이 있음을 발견하고, Spitzer data를 이용하여 이 IR source에 대하여 자세히 분석한다. 24 um image에서 IR source는 bipolar feature를 보이며, 매우 강한 중앙지역은 8 um 에서도 extended feature를 보여준다. Spitzer IRS spectrum에서는 [Ne II] 12.88 um 방출선이 강하게 나오는 것이 특징이며, 우리는 또한 이 IR source에 embedded 된 것으로 의심되는 point source를 분석한다.

• Journal of information and communication convergence engineering
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• 제16권4호
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• pp.228-234
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• 2018

In software development, the quality of a product often depends on whether its developers can rapidly find and contribute to the proper tasks. Currently, the word data of projects to which newcomers have previously contributed are mainly utilized to find appropriate source files in an ongoing project. However, because of the vocabulary gap between software projects, the accuracy of source file identification based on information retrieval is not guaranteed. In this paper, we propose a novel source file identification method to reduce the vocabulary gap between software projects. The proposed method employs DBPedia Spotlight to identify proper source files based on semantic similarity between source files of software projects. In an experiment based on the Spring Framework project, we evaluate the accuracy of the proposed method in the identification of contributable source files. The experimental results show that the proposed approach can achieve better accuracy than the existing method based on comparison of word vocabularies.

• International journal of advanced smart convergence
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• 제11권4호
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• pp.28-40
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• 2022

Although precise temperature control in the heat treatment process is a key factor in process reliability, there are many cases where there is no separate heat source control optimization system in the field. To solve this problem, the program monitors the temperature data according to the heat source change through sensor communication in a recursive method based on multiple variables that affect the process, and the target heat source value and the actual heat treatment heat source to match the internal air temperature and material temperature. A control optimization system was constructed. Through this study, the error rate between the target temperature and the atmosphere (material surface) temperature of around 10.7% with the existing heat source control method was improved to an improved result of around 0.1% using a process optimization algorithm and system.

• 상하수도학회지
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• 제26권6호
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• pp.815-823
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• 2012

Non-point source pollutants in down stream of Nakdong river were simulated by SWAT. GIS was utilized to make input data of SWAT such as landuse pattern and soil. Meteorological data of 2007 and 2009 were applied for the calibration and validation of runoff in SWAT. It was difficult to calibrate and validate the runoff and nutrient results since a study area was influenced by the tidal effects. Jindong site was selected to escape from the bias of runoff simulation in the coastal area. $R^2$ values of calibration and validation were 0.8 and 0.79. However, $R^2$ values of water qualities were very low level in comparison to runoff. These resulted from the concentration scale of water qualities such as BOD, T-N and T-P. Additionally, tidal influence could effected on the measurements of nutrients. The simulated annual averages and patterns of BOD, T-N and T-P in SWAT were similar to the measurement data. 80 ~ 96 % of nonpoint source pollutants at Nakbon M site were released from April to August of 2009. The ratio of T-N and T-P from nonpoint source were above 50 % during the rainy season.

• Spatial Information Research
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• 제22권2호
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• pp.45-52
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• 2014

최근 몇 년 동안 하천오염 관리의 중요성이 증가하고 중앙 및 지방정부는 하천오염 문제를 해결하기 위해 지속적인 노력을 하고 있다. 본 논문에서는 공간데이터와 오염원 정보의 응용 프로그램에 대해 살펴보고자 한다(항공사진, 지적정보, 오염원, GPS 데이터 등). 본 논문의 목적은 하천오염 관리시스템의 개발을 위해 공간정보의 응용 프로그램을 제공하는 것으로 보다 자세한 프레임웍을 보여 주기 위해 GPS 및 GIS를 적용하여 하천 오염원의 정량적 분석과 관리계획을 수행 하였다. 그런 이유에서 공간분석을 통한 하천오염 관리시스템을 구축 하였다. 본 연구가 도심하천 오염원 보전에 관한 관리정책 수립에 기여할 것을 기대한다.

• 한국정보시스템학회지:정보시스템연구
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• 제25권4호
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• pp.121-139
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• 2016

Purpose In this study, we propose the special purposed R package named ""new_Noun()" to process nonstandard texts appeared in various social networks. As the Big data is getting interested, R - analysis tool and open source software is also getting more attention in many fields. Design/methodology/approach With more than 9,000 R packages, R provides a user-friendly functions of a variety of data mining, social network analysis and simulation functions such as statistical analysis, classification, prediction, clustering and association analysis. Especially, "KoNLP" - natural language processing package for Korean language - has reduced the time and effort of many researchers. However, as the social data increases, the informal expressions of Hangeul (Korean character) such as emoticons, informal terms and symbols make the difficulties increase in natural language processing. Findings In this study, to solve the these difficulties, special algorithms that upgrade existing open source natural language processing package have been researched. By utilizing the "KoNLP" package and analyzing the main functions in noun extracting command, we developed a new integrated noun processing package "new_Noun()" function to extract nouns which improves more than 29.1% compared with existing package.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1752-1761
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• 2000

This paper describes the far-field estimation using the near-field measurement data. Measurement in far-field region gives us the acoustical characteristics of the source but in general measurement is made in near-field such as acoustic water tank or anechoic chamber, so far-field acoustical characteristics of the source should be predicted from near-field data. In this case, the number of measurement points in the near field which relates to the accuracy of the predicted field and the amount of data processing, should be optimized. Existing papers say that measurement points is proportional to kL and depends on geometry and directivity of the source. But they do not give us any definite criterion for the required number of measurement points. Boundary Collocation Method which is one of the far-field prediction methods, is analyzed based on Helmholtz integral equation and Green function and it has been found that the number of measurement points is optimized as 0.54kL which is about one half of the existing results.

• 음성과학
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• 제10권3호
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• pp.213-224
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• 2003

Spoken sound includes not only speaker's source but the characteristics of vocal tract and speech radiation. This paper is based on the theory of Park[1], who proposes the Phonation Type Index k; a variable that shows the characteristic of speaker's source excluding those of speaker's vocal tract and speech radiation. With Park's theory, we collect data by changing recording environments and expanding experimental data, and analyze the data collected to see whether or not the PTI k shows good discriminating power as a variable for speaker recognition. In the experiment, we repeatedly record 8 sentences ten times for each of 5 males in the environment of a recording room and an office, extract PTI k for each speaker, and measure the discriminating power for each speaker by using the value of PTI k. The result shows that PTI k has the excellent discriminating power of speakers. We also confirm that, even if the recording environment is changed, PTI k shows similar results.

• 천문학회보
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• 제37권2호
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• pp.137.1-137.1
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• 2012

If all Coronal mass ejections (CMEs) have flux ropes, then the CMEs should keep their helicity signs from the Sun to the Earth according to the helicity conservation principle. We select 34 CME-ICME pairs whose source active regions (ARs) have continuous SOHO/MDI magnetogram data covering more than 24 hr without data gap during the passage of the ARs near the solar disk centre. The helicity signs in the ARs are determined by estimation of accumulating amounts of helicity injections through the photospheric surfaces in the entire source ARs. The helicity signs in the ICMEs are estimated by applying the cylinder model developed by Marubashi (2000) to 16 second resolution magnetic field data from the MAG instrument onboard the ACE spacecraft. It is found that 30 out of 34 events (88%) are helicity sign-consistent events, while 4 events (12%) are sign-inconsistent. Through a detailed investigation of the AR solar origins of the 4 exceptional events, we find that those exceptional events can be explained by the local AR helicity sign opposite to that of the entire AR helicity (2000 July 28 ICME), incorrectly reported solar source in CDAW (2005 May 20 ICME), or the helicity sign of the pre-existing coronal magnetic field (2000 October 13 and 2003 November 20 ICMEs). We conclude that the helicity signs of the ICMEs are quite consistent with those of the injected helicities in the AR regions where CMEs were erupted.