• Communications for Statistical Applications and Methods
• /
• v.22 no.2
• /
• pp.159-172
• /
• 2015

This paper considers the problem of reconstructing an underlying signal from noisy data. This paper presents a reconstruction method based on synchrosqueezed wavelet transform recently developed for multiscale representation. Synchrosqueezed wavelet transform based on continuous wavelet transform is efficient to estimate the instantaneous frequency of each component that consist of a signal and to reconstruct components. However, an objective selection method for the optimal number of intrinsic mode type functions is required. The proposed method is obtained by coupling the synchrosqueezed wavelet transform with cross-validation scheme. Simulation studies and musical instrument sounds are used to compare the empirical performance of the proposed method with existing methods.

• Proceedings of the Korea Inteligent Information System Society Conference
• /
• 2002.05a
• /
• pp.201-202
• /
• 2002

No Abstract(See Full Text)

• Atmosphere
• /
• v.34 no.2
• /
• pp.187-202
• /
• 2024

We analyzed the observed characteristics of monoterpene and developed an empirical formula for monoterpene concentration in the pine-dominated mixed forest of the National Center for Forest Therapy. Monoterpene was measured at 0800, 1200 and 1700 LST once a month using sorbent tube sampling coupled with thermal desorption gas chromatography and mass spectrometry. Monoterpene concentration is low in winter and shows a maximum in June and July. The major components of monoterpene are alpha-pinene, camphene and beta-pinene. During the warm period from May to November, monoterpene concentration is higher at 0800 and 1700 LST than at 1200 LST. The empirical formula takes into account the vegetation variables, temperature-controlled emission, oxidation processes and dilution by wind. The vegetation variable accounts for the difference in observed monoterpene concentration between two sites. The observed monoterpene concentration normalized by the vegetation variable increases exponentially with air temperature. The oxidation process explains the lower monoterpene concentration at 1200 LST than at 0800 and 1700 LST during the warm period. The monoterpene estimates using the empirical formula shows a correlation of 0.52 with the observation for the development period (2018~2020), while it shows a correlation of 0.72 for the validation year (2021). Such higher correlation for the validation year than for the development period is due to the fact that variability of monoterpene concentration is better explained by air temperature in 2021 than in the development period. However, the developed formula underestimates the monoterpene concentration in May and June, showing the limitation in accurately capturing the monthly variation of monoterpene.

• Science of Emotion and Sensibility
• /
• v.20 no.3
• /
• pp.71-88
• /
• 2017

This paper compared self-validation and regulatory focus between consumers who felt happy vs. sad prior to decision and explored the effects of self-validation on regulatory focus and information distortion. The results of empirical analysis are as follows. First, consumers who felt happy beforehand revealed larger self-validation and stronger promotion focus than those who felt sad in advance. Second, compared to sadness, just-felt happiness was found to have partially positive impact on promotion focus by means of self-validation and exercise entirely positive impact on information distortion through mediation of self-validation. This study has made theoretic contributions by identifying the differences in the extent of self-validation and promotion focus between happiness and sadness as ambient emotion felt prior to the impending decision making as well as by investigating the effects of self-validation upon information distortion.

• Proceedings of the Korea Database Society Conference
• /
• 2000.11a
• /
• pp.27-37
• /
• 2000

o An Enriched conceptualization of BM o Needs further research on: - An Integrative framework for BM research - A dynamic. evolutionary account of BM - Empirical validation of the analysis models - Draw practical implications and guidelines for business (omitted)

• International Journal of Internet, Broadcasting and Communication
• /
• v.15 no.2
• /
• pp.218-226
• /
• 2023

In Korea, we still use function point based cost estimations for software size and cost of a project. The current problem is that we make difficultly calculating function points with requirements and also have less accurate. That is, it is difficult for non-experts to analyze requirements and calculate function point values with them, and even experts often derive different function points. In addition, all stakeholders strongly make the validity and accuracy of the function point values of the project before /after the development is completed. There are methods for performing function point analysis using source code [1][2][3][4] and some researchers [5][6][7] attempt empirical verification of function points about the estimated cost. There is no research on automatic cost validation with source code after the final development is completed. In this paper, we propose automatically how to calculate Function Points based on natural language requirements before development and prove FP calculation based on the final source code after development. We expect validation by comparing the function scores calculated by forward engineering and reverse engineering methods.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.46 no.4
• /
• pp.74-92
• /
• 2023

The computer system validation consulting industry is growing as domestic GMP companies' overseas exports or advancements increase, and computer system validation has been mandatory in Korea since the 2010s, but domestic CSV consulting companies are small in size and have a short history, revealing many shortcomings in terms of service quality and customer satisfaction when conducting consulting. Research related to consulting has been mainly focused on management consulting and IT consulting, and research related to computer system validation is very insufficient. This study confirmed the effect of consultant competency and service quality on consulting performance, customer satisfaction, and intention to renew contract when performing computer system validation through empirical research on food, pharmaceutical, cosmetics, and medical device companies, which are representative companies in the GMP industry. As a result, it was confirmed that consultant competency and service quality had a significant effect on consulting performance, customer satisfaction, and intention to renew contract. In addition, it was confirmed that the reputation and expertise of consulting companies had a moderating effect on the relationship between consultant competency and consulting performance.

• Journal of Environmental Science International
• /
• v.33 no.7
• /
• pp.523-532
• /
• 2024

In popular tourist destinations such as Jeju and Gangwon, electric rental cars are increasingly adopted. However, sudden battery drain due to weather conditions can pose safety issues. To address this, we developed a battery consumption analysis model that considers resistive energy factors such as acceleration, rolling resistance, and aerodynamic drag. Focusing on the effects of ambient temperature and wind speed, the model's performance was evaluated during an empirical validation period from November to December 2023. Comparing predicted and actual state of charge (SoC) across different routes identified ambient temperature, wind speed, and driving time as major sources of error. The mean absolute error (MAE) increased with lower temperatures due to reduced battery efficiency. Higher wind speeds on routes 1 and 6 resulted in larger errors, indicating the model's limitation in considering only tailwinds for aerodynamic drag calculations. Additionally, longer driving times led to higher actual SoC than predicted, suggesting the need to account for varying driver habits influenced by road conditions. Our model, providing more accurate SoC predictions to prevent battery depletion incidents, shows high potential for application in navigation apps for electric vehicle users in tourist areas. Future research should endeavor to the model by including wind direction, HVAC system usage, and braking frequency to improve prediction accuracy further.

• Journal of Korean Society for Quality Management
• /
• v.37 no.1
• /
• pp.40-55
• /
• 2009

This research is an empirical study to analyze the factors that affect users' acceptance & diffusion of online product message. Today many people use the product message/information on the internet, before they make decision to buy something in online/offline environment. This paper proposes the site design look, enjoyment, and usefulness as message perception factors. And we examine the relationship among the perception factors, message credibility, acceptance & diffusion. The purpose of this paper is threefold. First, we examine the relationship between as perception factors and the credibility assessment of the message by customers. Second, we will show the effect of message credibility on the message acceptance & diffusion. Third, we try to present some theoretical and empirical implication through the result of our studies.

• Membrane and Water Treatment
• /
• v.2 no.4
• /
• pp.225-237
• /
• 2011

In this study, response of reversibility of membrane flux during chemically enhanced backwash (CEB) to changes in filtration time, filtration flux and coagulant concentration dosing during ultrafiltration (UF) process was investigated using a regression model. The model was developed via empirical modelling approach using response surface methodology. In developing the model, statistically designed UF experiments were conducted and the results compared with the model output. The results showed that the performance of CEB, evaluated in terms of the reversibility of the membrane flux, depends strongly on the changes in coagulant concentration dosage and the filtration flux. Also the response of the reversibility of membrane flux during CEB is independent of the filtration time. The variance ratio, VR << $F_{value}$ and $R^2$ = 0.98 obtained from the cross-validation experiments indicate perfect agreement of the model output with experimental results and also testify to the validity and suitability of the model to predict reversibility of the membrane flux during CEB in UF operation.