• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.3
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• pp.277-284
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• 2014

This paper describes the application method of bumper area defined in the ship domain theory and it is to identify risky sectors in VTS(Vessel Traffic Services) area. The final goal of this work is to develop early warning system providing the location information with high traffic risks in Mokpo VTS area and to prevent the human errors of VTS Officer(VTSO). The current goal of this paper is to find evaluation and detection method of risky sectors. The ratio between overlapped bumper area of each vessels and the summing area of a designated sector, Ratio to Evaluate Risk(RER) ${\gamma}$ is used as one of evaluation and detection parameter. The usability of overlapped bumper area is testified through three kinds of scenarios for various traffic situations. The marine traffic data used in the experiments is collected by AIS(Automatic Identification System) receiver and then compiled in the SQL(Structured Query Language) Server. Through the analysis of passing vessel's tracks within the boundary of Mokpo VTS area, the total of 11 sectors are identified as evaluation unit sector. As experiment results from risk evaluation for the 11 sectors, it is clearly known that the proposed method with RER ${\gamma}$ can provide the location information of high risky sectors which are need to keep traffic tracks of vessel movements and to maintain traffic monitoring by VTSO.

• The Journal of the Acoustical Society of Korea
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• v.41 no.1
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• pp.30-37
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• 2022

This paper compares and evaluates model performance from two perspectives according to the learning target and network structure for training Deep Neural Network (DNN)-based speech enhancement models in the frequency domain. In this case, spectrum mapping and Time-Frequency (T-F) masking techniques were used as learning targets, and a real network and a complex network were used for the network structure. The performance of the speech enhancement model was evaluated through two objective evaluation metrics: Perceptual Evaluation of Speech Quality (PESQ) and Short-Time Objective Intelligibility (STOI) depending on the scale of the dataset. Test results show the appropriate size of the training data differs depending on the type of networks and the type of dataset. In addition, they show that, in some cases, using a real network may be a more realistic solution if the number of total parameters is considered because the real network shows relatively higher performance than the complex network depending on the size of the data and the learning target.

• Journal of the Korean School Mathematics Society
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• v.26 no.2
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• pp.137-158
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• 2023

This study aimed to analyze the shifts in the mathematics domains of the College Scholastic Ability Test (CSAT) since its inception in 1993, with the intent of identifying improvements for the future. The goal is to provide insights for exploring the direction of assessment in Korean high school mathematics education. To this end, we focused on the test system, content area, and behavioral area within the CSAT mathematics domains. Key findings include: first, the test structure influences the assessment factors and item types, in addition to the examination time and number of items. Second, by analyzing the content area, we established a correlation between the national curriculum and assessment area, and confirmed the importance of setting the assessment area. Third, the examination of the behavioral area tended to the item-type fixation, demonstrating the necessity of the ongoing modifications in evaluation item types. Building upon these findings, we discuss the direction of an evaluation that considers the evolving demands and shifts within mathematics education.

• Journal of Information Technology Applications and Management
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• v.11 no.2
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• pp.45-64
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• 2004

Many researchers have proved that information systems auditing is a very effective tool for improving information systems quality. However, information system auditing in Korea still includes many subjective judgements. This study deals with applying a quantitative model to improve information system auditing quality on security domain. First of all, we have looked at previous researches on information systems audit, especially on security audit. Based on this survey, we have come up with solutions to improve the evaluation efficiency on security audit. We have merged the security audit guidelines of NCA and KISA, and developed a quantified evaluation scheme. We have proved the validity of this model by interviews with experts and by case studies.

• Journal of KSNVE
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• v.9 no.3
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• pp.577-586
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• 1999

Estimation of damping ratio for vibration signals measured on the passenger car's sear is useful for the objective evaluation of impact harshness in car. The vibratio signal is a transient signal represented by many coupled modes of suspension system. Wavelet transform automatically decouples these modes in the time-frequency domain. Damping ratios for decoupled modes are obtained by logarithmic treatment for the Wavelet transformed signal. The objective evaluation using Wavelet transform has been well corresponded with subjective evaluation done by skilled engineers.

• Journal of the Korean Society of Systems Engineering
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• v.17 no.1
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• pp.43-52
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• 2021

The aim of this study is to propose the design suitable for sustainability evaluation model of the mobile industry considering system process (SEP). Although a quantitative evaluation was conducted on the link between the national sustainability report and the mobile industry, it was confirmed that it was difficult to identify stakeholders. So it is necessary to develop the design process suitable for the more operator-specific interfaces. The Human System Integration (HSI) methodology was proposed through linkage with work domain analysis. Agile methodology and Resilience engineering methodology were added for sustainable model design. The proposed sustainability system evaluation model is applied so that it can be easily used in all industries.

• Journal of the Korean Society for information Management
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• v.19 no.2
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• pp.109-130
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• 2002

This paper is mainly concerned with the matter of how organizational knowledge is represented in terms of usability by letting the members of the organization evaluate knowledge items in the problem solving situations. Organizational knowledge can be represented in the form of a visualized dynamic knowledge map since the organizational members experience constant changes in goals, kinds of problems, and the importance of alternatives to solve the given problems. The dynamic map suggested in this study is goal oriented in the sense that it represents the relationship between knowledge items across domains as well as within a domain.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.252-258
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• 2012

A study of terahertz waves was made for the nondestructive evaluation of FRP (Fiber reinforced plastics) composite materials. The terahertz systems were consisted of time domain spectroscopy (TDS) and continuous wave (CW). The composite materials investigated include both non-conducting polymeric composites and conducting carbon fiber composites. Terahertz signals in the TDS mode resembles that of ultrasound; however, unlike ultrasound, a terahertz pulse was not able to detect a material with conductivity. The CFRP (Carbon fiber reinforced plastics) laminates were utilized for confirming the experimentation in the terahertz NDE. In carbon composites the penetration of terahertz waves is quite limited and the detection of flaws is strongly affected by the angle between the electric field direction of the terahertz waves and the intervening fiber directions. A refractive index (n) was defined as one of mechanical properties; so a method was obtained in order solve the "n" in the material with non-conductivity. The usefulness and limitations of terahertz radiation are investigated for the NDE of FRP composites.

• IE interfaces
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• v.17 no.1
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• pp.33-45
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• 2004

In the web environment for general information seeking and business-to-customer and business-to-business electronic commerce, users are customers. Understanding their expectations and how they feel about the web sites they use is becoming a very serious concern. While the success of a company or an organization is dependent on many factors, its web site plays a central role. This paper described the use of WebQual2.0 to evaluate the various web sites of B2B and B2C. WebQual2.0 has been extended and refined to encompass an interaction-quality literature. Furthermore, this paper described the use of Kano model to evaluate the various web sites which classified by internet business types. The result showed that the inherent characteristics of B2B and B2C web site should be considered in initial site construction. Further, customers in a web domain do not regard all quality factors as equally important and the rankings of important quality factors differ from one web domain to another. This study was focused on the identifying the weights of web quality factors according to the each web site of the internet business types.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.1
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• pp.102-108
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• 2012

A study of terahertz waves (T-ray) was made for the nondestructive evaluation of FRP (Fiber reinforced plastics) composite materials. The to-be-used systems were time domain spectroscopy (TDS) and continuous wave (CW). The composite materials investigated include both turbine blades of wind energy (non-conducting polymeric composites) and conducting carbon fiber composites. Terahertz signals in the TDS mode resembles that of ultrasound; however, unlike ultrasound, a terahertz pulse was not able to detect a material with conductivity. This was demonstrated in CFRP (Carbon fiber reinforced plastics) laminates. Refractive index (n) was defined as one of mechanical properties; so a method was solved in order solve the "n" in the material with the cut parts of the turbine blades of wind energy. The defects and anomalies investigated by terahertz radiation were foreign material inclusions and simulated disband. Especially, it is found that the T-ray went through the turbine blade with greater thickness (about 90mm).