• Journal of Korean Society for Quality Management
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• v.41 no.3
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• pp.327-335
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• 2013

Purpose: The purpose of this study is to suggest the modified 'Korean Standard-Quality Excellence Index' model and analyze the improvement effect with survey data by comparing the properness between current and suggested model result. Methods: The collected data through the survey were analyzed using paired t-test and unbalanced ANOVA method for testing the consistency of two customer satisfaction evaluating categories and comparing the current model to suggested model for confirming the improvement of performance. Results: The statistical analysis result shows that adjusted model using prior information improves the consistency between two customer satisfaction in case of short life-cycle product. Also long life-cycle product case, the result shows difference gap decreasing with same direction. Conclusion: Considering statistical model for QEI reflecting the characteristic of product group such as life cycle seems to be meaningful. Since index may be compared yearly base for checking the trend, careful approaching without big change should be considered for application.

• The Korean Journal of Applied Statistics
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• v.19 no.2
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• pp.349-360
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• 2006

PROC MIXED in SAS can be utilized to make inferences on parameters in a mixed model by use of Restricted Maximum Likelihood Estimation Method or Maximum Likelihood Estimation Method which has more merits than ANOVA method. A regression model with unbalanced nested error structure that belongs to a mixed model is used to construct confidence intervals on variances among groups, within groups, and regression coefficients in the model. PROC MIXED is applied to three different sample sizes for simulation. As a result of the simulation study, PROC MIXED generates confidence intervals on parameters that maintain the stated confidence coefficient in a large sample size. However, it does not generate confidence intervals that maintain the stated confidence coefficient for variance components among groups and intercept in a small sample size.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.6
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• pp.174-186
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• 2001

Excessive outflow of pollutant loads resulting from rapid industrialization has unbalanced the water ecosystem, deteriorating the water quality environment severely. Therefore, measures for improving the water quality are necessary to maintain clean reservoir water and restore water-friendly spaces. A water quality model which is capable of simulating daily reservoir water quality was developed. The model had been applied to Masan reservoir and Wanggung reservoir in Korea. The model appeared to be satisfactory in representing the trend of water quality variations by comparing measured and simulated results. The model had been also applied to assess water purification techniques such as dredged pool, floating island and vegetation purification system. The model was considered to assess the effect of water purification techniques on reservoir water quality improvement. The results of water quality simulation for lake water purification techniques showed that a large facility would be needed to meet the targeted water quality of the reservoir when only one technique is applied. To effectively improve the quality of the polluted reservoir water, it is therefore recommended that pollutant sources should first be controlled, and a combination of the water purification techniques applied to make the utmost use of their secondary effects such as conservation of the reservoir volume capacity, establishment of a recreation space, promotion of bio-diversity, and improvement of the lake landscape.

• Korean Journal of Remote Sensing
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• v.25 no.3
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• pp.271-285
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• 2009

Multi-temporal satellite imagery can be changed into a transform image that emphasizes the changed area only through the application of various change detection techniques. From the transform image, an automated change detection model calculates the optimal threshold value for classifying the changed and unchanged areas. However, the model can cause undesirable results when the histogram of the transform image is unbalanced. This is because the model uses a single threshold value in which the sign is either positive or negative and its value is constant (e.g. -1, 1), regardless of the imbalance between changed pixels. This paper proposes an advanced method that can improve accuracy by applying separate threshold values according to the increased or decreased range of the changed pixels. It applies multiple threshold values based on the cumulative producer's and user's accuracies in the automated binary change detection model, and the analyst can automatically extract more accurate optimal threshold values. Multi-temporal IKONOS satellite imagery for the Daejeon area was used to test the proposed method. A total of 16 transformation results were applied to the two study sites, and optimal threshold values were determined using accuracy assessment curves. The experiment showed that the accuracy of most transform images is improved by applying multiple threshold values. The proposed method is expected to be used in various study fields, such as detection of illegal urban building, detection of the damaged area in a disaster, etc.

• International Journal of Advanced Culture Technology
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• v.10 no.4
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• pp.499-510
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• 2022

This study examines the reporting factors of crime against business in Korea and proposes a corresponding predictive model using machine learning. While many previous studies focused on the individual factors of theft victims, there is a lack of evidence on the reporting factors of crime against a business that serves the public good as opposed to those that protect private property. Therefore, we proposed a crime prevention model for the willingness factor of theft reporting in businesses. This study used data collected through the 2015 Commercial Crime Damage Survey conducted by the Korea Institute for Criminal Policy. It analyzed data from 834 businesses that had experienced theft during a 2016 crime investigation. The data showed a problem with unbalanced classes. To solve this problem, we jointly applied the Synthetic Minority Over Sampling Technique and the Tomek link techniques to the training data. Two prediction models were implemented. One was a statistical model using logistic regression and elastic net. The other involved a support vector machine model, tree-based machine learning models (e.g., random forest, extreme gradient boosting), and a stacking model. As a result, the features of theft price, invasion, and remedy, which are known to have significant effects on reporting theft offences, can be predicted as determinants of such offences in companies. Finally, we verified and compared the proposed predictive models using several popular metrics. Based on our evaluation of the importance of the features used in each model, we suggest a more accurate criterion for predicting var.

• ETRI Journal
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• v.25 no.2
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• pp.89-100
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• 2003

The notion of pseudorandomness is the theoretical foundation on which to consider the soundness of a basic structure used in some block ciphers. We examine the pseudorandomness of the block cipher KASUMI, which will be used in the next-generation cellular phones. First, we prove that the four-round unbalanced MISTY-type transformation is pseudorandom in order to illustrate the pseudorandomness of the inside round function FI of KASUMI under an adaptive distinguisher model. Second, we show that the three-round KASUMI-like structure is not pseudorandom but the four-round KASUMI-like structure is pseudorandom under a non-adaptive distinguisher model.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.35-40
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• 2007

The one step type and two step type pole are used in distribution line. If the three phases are not balanced, the communication line can be damaged by induced voltage. This paper calculates the neutral current using KEPCO's distribution system model which is only composed by one step type pole. The used system model is modelled by using ATPDraw and the neutral current is calculated by using EMTP/MODELS. Many cases for abstracting the neutral current characteristics in KEPCO's distribution system are simulated and analyzed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.8
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• pp.1108-1114
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• 2013

This paper presents a new winding topology for MW class offshore wind generator having modular and dual 3-phase. Based on proposed simplified relationship between magnetic flux and phase current in the air gap, several new windings for modular and dual 3-phase are made. In case of one inverter operation or faulty operation, the proposed model can have balanced 3-phase induced voltage whereas the conventional generator with modular winding has unbalanced induced voltage, which can be important issue in offshore generator. The model was applied into 6MW prototype machine with dual 3-phase. Using finite element analysis, induced voltage, inductance were investigated. The results show that the proposed modular winding can be applicable to dual inverter system with electrically balanced voltage.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.7
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• pp.1194-1198
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• 2010

A high temperature superconducting power cable (HTS power cable) was applied large current capacity by no resistance in normal state. Fault state was risen out of over-current but, it was limited to resistance. this study was modeling equivalence, and unbalanced state analyzed operating charateristics of HTS power cable. The equivalence model was composed superconductor, shield, and former part. This model simulation was appeared conductor and shield current in normal state, but fault state was appeared former current as rise current by resistance. so it need to sufficiently influenced the quench characteristic when the former design.

• East Asian Economic Review
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• v.23 no.2
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• pp.169-202
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• 2019

Productivity in agriculture or services has long been understood as playing an important role in the growth of manufacturing. In this paper we present a general equilibrium model in which manufacturing growth is stimulated by non-manufacturing sectors that provides goods used in both research and final consumption. The model permits the evaluation of two policy options for stimulating manufacturing growth: (1) a country imports more non-manufacturing goods from a foreign country with higher productivity and (2) a country increases productivity of domestic non-manufacturing. We find that both policies improve welfare of the economy, but depending on the policy the manufacturing sector responses differently. Specifically, employment and value-added in manufacturing increase with policy (1), but contract with policy (2). Therefore, specialization of the import non-manufactured goods helps explain why some Asian economies experience rapid growth in the manufacturing sector without progress in other sectors.