• Journal of Korean Society of Water and Wastewater
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• v.16 no.6
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• pp.710-716
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• 2002

A General Pipe Break Prediction Model that incorporates linear and exponential models in its form is developed. The model is capable of fitting pipe break trends that have linear, exponential or in between of linear and exponential trend by using a weighting factor. The weighting factor is adjusted to obtain a best model that minimizes the sum of squared errors of the model. The model essentially plots a best curve (or a line) passing through "cumulative number of pipe breaks" versus "break times since installation of a pipe" data points. Therefore, it prevents over-predicting future number of pipe breaks compared to the conventional exponential model. The optimal replacement time equation is derived by using the Threshold Break Rate equation by Loganathan et al. (2002).

• Communications for Statistical Applications and Methods
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• v.19 no.1
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• pp.177-182
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• 2012

A structural break in the level as well as in the innovation variance has often been exhibited in economic time series. In this paper we propose robust unit root tests based on a sign-type test statistic when a time series has a shift in its level and the corresponding volatility. The proposed tests are robust to a wide class of partially stationary processes with heavy-tailed errors, and have an exact binomial null distribution. Our tests are not affected by the size or location of the break. We set the structural break under the null and the alternative hypotheses to relieve a possible vagueness in interpreting test results in empirical work. The null hypothesis implies a unit root process with level shifts and the alternative connotes a stationary process with level shifts. The Monte Carlo simulation shows that our tests have stable size than the OLSE based tests.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.193-206
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• 2022

Several algorithms for nuclear power plant (NPP) break event detection, isolation, localization, and size estimation are proposed. A break event can be promptly detected and isolated after its occurrence by simultaneously monitoring changes in the sensing readings and by employing an interquartile range-based isolation scheme. By considering the multi-sensor data block of a break to be rank-one, it can be located as the position whose lead field vector is most orthogonal to the noise subspace of that data block using the Multiple Signal Classification (MUSIC) algorithm. Owing to the flexibility of deep neural networks in selecting the best regression model for the available data, we can estimate the break size using multiple-sensor recordings of the break regardless of the sensor types. The efficacy of the proposed algorithms was evaluated using the data generated by Maanshan NPP simulator. The experimental results demonstrated that the MUSIC method could distinguish two near breaks. However, if the two breaks were close and of small sizes, the MUSIC method might wrongly locate them. The break sizes estimated by the proposed deep learning model were close to their actual values, but relative errors of more than 8% were seen while estimating small breaks' sizes.

• Speech Sciences
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• v.4 no.1
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• pp.113-133
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• 1998

The system proposed in this paper prosodically transcribes the intonation patterns, prosodic structures, phrasings, and other prosodic aspects of Korean utterances, on four parallel tiers: a tone tier, an orthographic tier, a break index tier, and a miscellaneous tier. The tone tier employs two phrase accents (L* and H *), three accentual phrase boundary tones (L-, H-, LH-), and four intonational phrase boundary tones (L%,H%,LH%,LHL%) in order to provide a phonological transcription of pitch events associated with accented syllables and phrase boundaries. The break index tier uses five break indices, numbered from 0 to 4, which mark a prosodic grouping of words and its prosodic structure in an utterance. Among the five indices, the break index 3 and the break index 4 align with an accentual phrase boundary tone and an intonational phrase boundary tone, respectively, in the tone tier.

• Speech Sciences
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• v.2
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• pp.159-172
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• 1997

This paper proposes a prosodic representation system of the Kyungnam dialect of Korean, based on the ToBI system. In this system, diverse intonation patterns are transcribed on the four parallel tiers: a tone tier, a break index tier, an orthographic tier, and a miscellaneous tier. The tone tier employs pitch accents, phrase accents, and boundary tones marked with diacritics in order to represent various pitch events. The break index tier uses five break indices, numbered from 0 to 4, in order to represent degrees of connectiveness in speech by associating each inter-word position with a break index. In this, each break index represents a boundary of some kind of constituent. This system can contribute not only to a more detailed theory connecting prosody, syntax, and intonation, but also to current text-to-speech synthesis approaches, speech recognition, and other quantitative computational modellings.

• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.702-708
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• 2019

This paper deals with break size estimation of loss of coolant accidents (LOCA) using a nonlinear autoregressive with exogenous inputs (NARX) neural network. Previous studies used static approaches, requiring time-integrated parameters and independent firing algorithms. NARX neural network is able to directly deal with time-dependent signals for dynamic estimation of break sizes in real-time. The case studied is a LOCA in the primary system of Bushehr nuclear power plant (NPP). In this study, number of hidden layers, neurons, feedbacks, inputs, and training duration of transients are selected by performing parametric studies to determine the network architecture with minimum error. The developed NARX neural network is trained by error back propagation algorithm with different break sizes, covering 5% -100% of main coolant pipeline area. This database of LOCA scenarios is developed using RELAP5 thermal-hydraulic code. The results are satisfactory and indicate feasibility of implementing NARX neural network for break size estimation in NPPs. It is able to find a general solution for break size estimation problem in real-time, using a limited number of training data sets. This study has been performed in the framework of a research project, aiming to develop an appropriate accident management support tool for Bushehr NPP.

• Journal of the Korea Convergence Society
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• v.11 no.7
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• pp.289-295
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• 2020

As the importance of the beauty to pursue beauty comes to the fore, the market size of hairdressing industry including hair dyeing is getting bigger. In case of continuously applying an oxidative dyeing agent commonly used in hair salons, as hair damage is inevitable, we investigated morphological changes of hair treated with a neutral oxidative dyeing agent. In the experiment results, Between the control and the 6N-7N experimental groups, there was a significant difference in Max. modulus and Tangential modulus according to Max. load, Max. stress, Max. elongation, Break load, Break stress, Break elongation, and strain section. There were the highest values in Max. load, Max. stress, Max. elongation, Break load, Break stress and Break elongation in the control group, and there was no tendency to decrease significantly according to the treatment of the experimental group. Max. modulus and Tangential modulus according to the strain evaluation section did not show a tendency to increase or decrease constantly, although there was a difference between the control and experimental groups. This study attempts to provide basic data for the development of oxidative dyeing agent that minimizes hair damage and to establish the foundation for understanding the correlation between hair designers' oxidative dyeing agent and hair health.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.2
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• pp.120-134
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• 2023

In this study, hydrodynamic characteristics of dam break flow were investigated by a series of experiments. The experiments were performed in a 2-D rectangular flume with obtaining instantaneous images of dam break flow to capture the free surface elevation, and pressure distributions on vertical wall and bottom of the flume. The initial water depth of the dam break flow was changed into 3 different heights, and the gate opening speed was changed during the experiments to study the effect of the gate speed in the dam break flow. Generation of dam break phenomena could be classified into three stages, i.e., very initial, relatively stable, and wall impact stages. The wall impact stage could be separated into 4 generation phases of wall impinge, run-up, overturning, and touchdown phases based on the deformation of the free surface. The free surface elevation were investigated with various initial water depth and compared with the analytic solutions by Ritter (1892). The pressures acting on the vertical wall and bottom were provided for the whole period of dam break flow varying the initial water depth and gate open speed. The measurement results of the dam break flow was compared with the hydrodynamic characteristics of green water phenomena, and it showed that the dam break flow could overestimate the green water loading based on the estimation suggested by Buchner (2002).

• IE interfaces
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• v.15 no.3
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• pp.279-285
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• 2002

A break-even analysis is a method used widely for profit planning or decisions in most companies. It is useful tool in financial studies because it is simple and offers useful insights from a modest amount of data. Although it is widely used, it has some weaknesses. It is limited in particular to the analysis for a short term time horizon or one period. We suggest a new break-even procedure to analyze projects with a long term time horizon as keeping the simplicity of a conventional break-even analysis. We will make efforts doing to include actual data for a cost or an income as much as possible rather than developing a mathematical model to improve unreality of a traditional break-even analysis. Also, we will use the spreadsheet software to solve problems.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.5
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• pp.441-448
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• 2011

Lately, digital restitution was became common using digital aerial photos. Therefore, we can obtain three-dimensional data. As a plotting-maker is checked by naked eye, plotting original data is very useful for making reliable three-dimensional data including contour and elevation point layers. In this study, we want to make precise and accurate digital elevation model using plotting original data. Contour and elevation point layers was extracted in digital map and break line was extracted in plotting original data. And then, compared both of results. For comparison, we selected slight slope and complex topography area like a residence area, mountain and agricultural land. We extracted break line deleting layer until obtaining ideal digital elevation model. As the results, We could extract contour, elevation points, eight road and two boundary layers using break lines. And We could obtain precise elevation model. Editing break lines, the distortion of digital elevation model could be minimized in the complex and sharp slope area.