• Korean Management Science Review
• /
• v.20 no.1
• /
• pp.103-124
• /
• 2003

The seasonal adjustment is an essential process in analyzing the time series of economy and business. There are various methods to adjust seasonal effect such as moving average, extrapolation, smoothing and X11. One of the powerful adjustment methods is X11-ARIMA Model which is popularly used in Korea. This method was delivered from Canada. However, this model has been developed to be appropriate for Canadian and American environment. Therefore, we need to review whether the Xl1-ARIMA Model could be used properly in Korea. In this study, we have applied the method to the annual sales of refrigerator sales in A electronic company. We appreciated the adjustment by result analyzing the time series components such as seasonal component, trend-cycle component, and irregular component, with the proposed method.

• Journal of the korean Society of Automotive Engineers
• /
• v.11 no.5
• /
• pp.65-75
• /
• 1989

A method for analyzing the heat dissipation rates of automotive radiators has been proposed and also a new model equation of heat transfer rate of louvered fins has been proposed and tested. With the method, the effect of various design parameters on the performance of a radiator has also been studied. The proposed model equation for air-side heat transfer has made fair predictions which agree well with the experiments. Also the design value of heat dissipation rate with various fin pitches and radiator size has a good agreement with the heat dissipation of the commercial automotive radiators. Thus, the method of analyzing the radiator performance proposed in this study might be used to design new automotive radiators.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2006.05a
• /
• pp.261-264
• /
• 2006

Many process parameters have an effect on the auto-body panel forming process. A well-designed blank shape causes the material to flow smoothly, reduces the punch and yields a product with uniform thickness distribution. Therefore, the determination of an initial blank shape plays the important role of saving time and cost in the auto-body panel forming process. For these reasons, some approaches to estimate the initial blank shape have been implemented in this paper, the one-step approach by using a finite element inverse method will be introduced to predict the initial blank shape the developed program is applied to auto-body panel forming.

• Asia pacific journal of information systems
• /
• v.26 no.1
• /
• pp.66-79
• /
• 2016

The availability of detailed data on customers' online behaviors and advances in big data analysis techniques enable us to predict consumer behaviors. In the past, researchers have built purchase prediction models by analyzing clickstream data; however, these clickstream-based prediction models have had several limitations. In this study, we propose a new method for purchase prediction that combines information theory with machine learning techniques. Clickstreams from 5,000 panel members and data on their purchases of electronics, fashion, and cosmetics products were analyzed. Clickstreams were summarized using the 'entropy' concept from information theory, while 'random forests' method was applied to build prediction models. The results show that prediction accuracy of this new method ranges from 0.56 to 0.83, which is a significant improvement over values for clickstream-based prediction models presented in the past. The results indicate further that consumers' information search behaviors differ significantly across product categories.

• Journal of Advanced Marine Engineering and Technology
• /
• v.30 no.2
• /
• pp.247-252
• /
• 2006

Almost ship monitoring systems are event driven alarm system which warn only when the measurement value is over or under set point. These kinds of system cannot warn until signal is growing to abnormal state that the signal is over or under the set point. therefore cannot play a role for preventive maintenance system. This paper proposes fault diagnosis method which is able to diagnose and forecast the fault from present operating condition by analyzing monitored signals with present ship monitoring system without any additional sensors. By analyzing the data with high correlation coefficient(CC), correlation level of interactive data can be defined. Knowledge base of abnormal detection can be built by referring level of CC(Fault Detection CC. FDCC) to detect abnormal data among monitored data from monitoring system and knowledge base of diagnosis built by referring CC among interactive data for related machine each other to diagnose fault part.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2005.06a
• /
• pp.281-286
• /
• 2005

Almost ship monitoring systems are event driven alarm system which warn only when the measurement value is over or under set point. These kinds of system cannot warn while signal is growing to abnormal state until the signal is over or under the set point and cannot play a role for preventive maintenance system. This paper proposes fault diagnosis method which is able to diagnose and forecast the fault from present operating condition by analyzing monitored signals with present ship monitoring system without additional sensors. By analyzing this data having high correlation coefficient(CC), correlation level of interactive data can be understood. Knowledge base of abnormal detection can be built by referring level of CC(Fault Detection CC, FDCC) to detect abnormal data among monitored data from monitoring system and knowledge base of diagnosis built by referring CC among interactive data for related machine each other to diagnose fault part.

• Proceedings of the KIEE Conference
• /
• 1990.07a
• /
• pp.11-14
• /
• 1990

The Complex Harmonic Balance Finite Element Method CHBFEM ) is dicussed for the time - periodic magnetic field with saturation characteristics. And Jw - method which is used for analyzing liner system with sinusoidal voltage input can be generalized in nonlinear time-periodic magnetio field system. The CHBFEM enables us to calculate the each harmonic magnetic flux ditribution and the distortion of currents resulting from material at an AC voltage source and to save calculating time, the number of calculation and computer memory.

• Journal of Welding and Joining
• /
• v.31 no.3
• /
• pp.54-59
• /
• 2013

Several methodologies analyzing welding distortions of large shell structures like ship blocks have been developed and utilized in shipyards for a long times ago. In general, one of objects of thermal distortion analysis is to find welding sequence making least-deformation without any suppliance, and it can be solved easily and rapidly by EP strain-boundary method. But after assembly construction, there are usually more than 10 weldments in each process, and the number of sequence will follow the Factorial calculation. In this research, a method has been suggested to decide the best welding sequence by minimum analysis. Using this method, welding deformation could be reduced just analyzing some cases as many as the number of weldments. Experiments and Analysis of all cases were also done, and their best results are good agreements with predictation by suggested methodology.

• ETRI Journal
• /
• v.33 no.5
• /
• pp.770-779
• /
• 2011

Security quad and cube (SQC) is a network attack analyzer that is capable of aggregating many different events into a single significant incident and visualizing these events in order to identify suspicious or illegitimate behavior. A network administrator recognizes network anomalies by analyzing the traffic data and alert messages generated in the security devices; however, it takes a lot of time to inspect and analyze them because the security devices generate an overwhelming amount of logs and security events. In this paper, we propose SQC, an efficient method for analyzing network security through visualization. The proposed method monitors anomalies occurring in an entire network and displays detailed information of the attacks. In addition, by providing a detailed analysis of network attacks, this method can more precisely detect and distinguish them from normal events.

• Journal of Environmental Science International
• /
• v.23 no.4
• /
• pp.533-541
• /
• 2014

The streams in Jeju Island have very distinctive hydrological and geological properties and there are a lot of limits in applying the general flood estimation method. This study presented parameters dominant in the Hancheon stream of Jeju Island by analyzing the sensitivity of parameters of HEC-HMS model regarding rainfall events in the target basin, and extracted the optimal parameter(Time of Concentration of Clark Unit Hydrograph: Kraven II method, Storage Coefficient: Sabol method) by analyzing and comparing it with the flood runoff data observed in the site and Jeju Island's observation data.