• Journal of Labour Economics
• /
• v.36 no.3
• /
• pp.65-96
• /
• 2013

Analysis based on the Korea Labor and Income Panel Survey data reveals that earnings have become less volatile since the exchange rate crisis, while they have become more unequal. The reduction in measured earnings volatility is not explained by changes in the composition of various economic/demographic groups but accounted for by within-group reduction in the measured earnings volatility, which in turn is attributed to the reduced earnings mobility during the sample period. It is also found that measured earnings volatility is countercyclical and earnings changes are symmetric even during recessions.

• Convergence Security Journal
• /
• v.10 no.3
• /
• pp.51-60
• /
• 2010

The expansion of internet technology has made convenience. On the one hand various malicious code is produced. The number of malicious codes occurrence has dramadically increasing, and new or variant malicious code circulation very serious, So it is time to require analysis about malicious code. About malicious code require set criteria for judgment, malicious code taxonomy using Algorithm of weakness difficult to new or variant malicious code taxonomy but already discovered malicious code taxonomy is effective. Therefore this paper of object is various malicious code analysis besides new or variant malicious code type or form deduction using visualization of strong. Thus this paper proposes a malicious code analysis and grouping method using visualization.

• Journal of KIISE
• /
• v.43 no.2
• /
• pp.135-142
• /
• 2016

Visual analysis of spatiotemporal data has focused on a variety of techniques for analyzing and exploring the data. The goal of these techniques is to explore the spatiotemporal data using time information, discover patterns in the data, and analyze spatiotemporal data. The overall trend flow patterns help users analyze geo-referenced temporal events. However, it is difficult to extract and visualize overall trend flow patterns using data that has no trajectory information for movements. In order to visualize overall trend flow patterns, in this paper, we estimate continuous distributions of discrete events over time using KDE, and we extract vector fields from the continuous distributions using the gravity model. We then apply our technique on twitter data to validate techniques.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.10B
• /
• pp.1111-1116
• /
• 2009

In this paper, we discuss distortion-tolerant pattern recognition using computational integral imaging reconstruction. Three-dimensional object information is captured by the integral imaging pick-up process. The captured information is numerically reconstructed at arbitrary depth-levels by averaging the corresponding pixels. We apply Fisher linear discriminant analysis combined with principal component analysis to computationally reconstructed images for the distortion-tolerant recognition. Fisher linear discriminant analysis maximizes the discrimination capability between classes and principal component analysis reduces the dimensionality with the minimum mean squared errors between the original and the restored images. The presented methods provide the promising results for the classification of out-of-plane rotated objects.

• The Korean Journal of Applied Statistics
• /
• v.33 no.4
• /
• pp.421-437
• /
• 2020

This paper implemented a method to predict the fertility rate, mortality rate, and international migration rate using the R program, which has been widely used in recent years, that calculates population projection by substituting the results into the Leslie matrix. In particular, the generalization log gamma model for the fertility rate by Kaneko (2003), LC-ER model for mortality rate by Li et al. (2013), and functional data model for international migration rates proposed by Ramsay and Silverman (2005) and Hyndman and Booth (2008), Hyndman et al. (2013) can be directly demonstrated with R programs. Demography and bayesPop have been introduced as a representative demographic package implemented in R; however, it can be analyzed only for data uploaded to Human Mortality Database (HMD) and Human Fertility Database (HFD) with data changes and modifications requiring application of other data. In particular, in Korea, there is a limitation in applying this package because it is provided only for short-term data in HMD. This paper introduces an R program that can reflect this situation and the different patterns of low fertility, aging, migration of domestic and foreigners in Korea, and derives a population projection for the year 2117.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.2
• /
• pp.157-165
• /
• 2015

With the ever-improving performance of smartphone cameras and the universal dissemination of cloud services, users can now record and store the events in their daily lives more easily and conveniently. The advent of lifelogging technology has been changing the uses as well as the paradigm of internet services, and emphasizing the importance of services being personalization. As the amount of lifelog data becomes vast, it requires an efficient way to manage and store such vast information. In this paper, we propose an low power lifelog management scheme based on user movement behaviors in wireless networks. In order to reduce the power consumption of a smartphone, in our proposal, frequency of data collection and transfer can be dynamically adjusted based on a user's movement pattern. The analytical results show that our approach achieves better performance than that of the existing lifelog management scheme.

• Journal of the Korean Geographical Society
• /
• v.42 no.6
• /
• pp.930-939
• /
• 2007

This study intends to demonstrate that the population decrease in the City of Busan has been resulted from the move of the city's population towards suburbs as well as the out-migration towards the Seoul metropolitan area. To grasp the pattern in the spatial shift of the Busan's population, I analyze the change of population and households within the city and the migration at the inter-regional and intra-metropolitan scales. The major findings of the study are as follows: First, Busan has experienced population decline since 1995, as other large cities, such as Seoul and Daegu have done. Second, despite the population decrease, the number of households has been increased in Busan. Third, the residents of Busan have mostly moved not only to the Seoul metropolitan area but also to the suburban region of Busan. This finding may well contradict the long-standing belief that the continued decrease in the Busan population could be the result of the out-migration toward the Seoul metropolitan area. Fourth, the residential suburbanization in Busan can be interpreted as the extensive intra-metropolitan dispersion, which means the growth of the Busan metropolitan area.

• Journal of Korea Multimedia Society
• /
• v.10 no.9
• /
• pp.1106-1116
• /
• 2007

Recently e-commerce trade on the web has grown rapidly in scale and complexity, just as web site designs and web servers have become more complicated. In view of these complexities, it is obviously difficult to analyse web user's data since they web users employ so many different web paths. The existing association rule investigation algorithms identify all items with a high correlation. However even though users often only want to find items in which they have interest, it is still difficult to find the rules they want out of all of the many association rules found by existing algorithms. In this paper, we propose a system linking each node with the sequence association rule, linking all routes after finding a path corresponding to a user with the association rule-one of the data mining techniques which identify user patterns in web user paths. The suggested system helps us construct individualized or customer-subdivided sites using the sequence association rule in order to harmonize the paths of web users with user characters.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.36 no.2
• /
• pp.75-83
• /
• 2023

In this paper, we present the analysis results on the vibration serviceability of a pedestrian bridge considering the effect of pedestrian moving mass inertia. Using dynamic finite element analysis, we considered different walking scenarios, including pedestrian density, walking speed, random walking, and synchronized walking, to analyze the acceleration response of a 40m long single-span bridge with a steel composite box cross section. We showed that the equivalent fixed mass analysis method did not significantly differ from the moving mass analysis in the random walk scenario and a wider frequency excitation band may be useful to consider when evaluating vibration serviceability in a random walk scenario.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.11
• /
• pp.1672-1678
• /
• 2022

In this paper, the relay antenna was designed in consideration of the performance of the 28GHz band 5G mobile communication relay horn antenna, such as radiation pattern and return loss. A horn array for 5G mobile communication repeater was designed by arranging the antenna elements in phase, and the performance was analyzed. Unlike conventional WCDMA (3G) and LTE (4G), in millimeter wave band communication, high path loss occurs between transmission and reception. In the design of a 5G millimeter wave horn antenna, antenna performance such as isolation and gain between antenna elements as well as gain and bandwidth of the antenna must be additionally considered. The antenna gain of the single horn antenna (1×1) and the array horn antenna (2×4) in the 28GHz band is about 10.44d Bi and 19.58dBi, respectively, and the return loss is designed to be less than -18dB. It has proven its validity and has been shown to be suitable for application to 5G mobile communication relay system.