• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.477-478
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• 2020

포트나이트는 전 세계적으로 엄청난 흥행을 거두었지만, 한국에서는 해외에 비해 흥행 성적이 좋지 하였다. 그 이유는 한국의 게임 시장이 해외와 다른 특성들이 있었고. 포트나이트는 이런 점들이 제대로 반영되지 않아 한국에서는 흥행이 부진하게 되었다. 본 논문에서는 한국에서 포트나이트가 해외에 비해 성공을 거두지 못한 원인들을 분석하고, 이런 분석결과를 바탕으로 포트나이트가 한국에서 흥행하기 위한 방안을 제시한다.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.48-58
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• 2013

The stock market is constantly changing and sometimes a slump or a sudden rising in stocks happens without any special reason. So the stock market is recognized as a complex system and it is hard to predict the change on stock prices. In this paper we consider the stock market to a network consisting of stocks. We analyzed the dynamics of the Korean stock market network and evaluated the changing of the correlation between shares consisting of the time series data of 137 companies belong to KOSPI200. Our analysis shows that the stock prices tend to plummet when the correlation between stocks is very high. We propose a method for recommending the stock portfolio based on the analysis of the stock market network. To show the effectiveness of the recommended portfolio, we conducted the simulated stock investment and compared the recommended portfolio with the efficient portfolio proposed Markowitz. According to the experiment results, the rate of return of the portfolio is about 10.6% which is about 3.7% and 5.6% higher than the average rate of return of the efficient portfolio and KOSPI200 respectively.

• The KIPS Transactions:PartD
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• v.18D no.4
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• pp.299-308
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• 2011

In the recent years, a variety of projects have been conducted in order to enhance competitiveness of leading businesses and their followers in the market. Accordingly, the importance of project portfolio management has risen in the open market industry. Project portfolio management refers to crucial decision-making processes which aim to maximize benefits by selecting projects most suitable for a strategic objective among multiple projects with limited resources. In this study, the trend of project portfolio management studies is introduced. The study also presents a mathematical model of the problem, which aims at maximizing project values, possibility, and similarity between projects in the limited resources. We use the genetic algorithm to obtain the priority orders of projects. In order to verify this study, we compare the results of this study and the existing schedules of the E-open market in South Korea. This study ultimately reduces project risks, improves efficiency of development and continuity of tasks by properly ordering projects and assigning developers to the projects.

• The Korean Journal of Applied Statistics
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• v.34 no.1
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• pp.39-56
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• 2021

Many researches have been done on portfolio optimization since Markowitz (1952) published a diversified investment model. Markowitz's mean-variance portfolio optimization problem is established under the assumption that the distribution of returns follows a normal distribution. However, in real life, the distribution of returns does not follow a normal distribution, and variance is not a robust statistic as it is heavily influenced by outliers. To overcome these potential issues, mean-shortfall portfolio model was proposed that utilized downside risk, shortfall, as a risk index. In this paper, we propose a perturbation method that uses the shortfall as a risk index of the portfolio. The proposed portfolio utilizes an adaptive Lasso to obtain a sparse and stable asset selection because it can reduce management and transaction costs. The proposed optimization is easily applicable as it can be computed using an efficient linear programming. In our real data analysis, we show the validity of the proposed perturbation method.

• Journal of the Institute of Convergence Signal Processing
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• v.23 no.4
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• pp.249-255
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• 2022

Potholes are an important clue to the structural defects of asphalt pavement and cause many casualties and property damage. Therefore, accurate pothole detection is an important task in road surface maintenance. Many machine learning technologies are being introduced for pothole detection, and data preprocessing is required to increase the efficiency of deep learning models. In this paper, we propose a preprocessing method that emphasizes important textures and shapes in pothole datasets. The proposed preprocessing method uses intensity transformation to reduce unnecessary elements of the road and emphasize the texture and shape of the pothole. In addition, the feature of the porthole is detected using Superpixel and Sobel edge detection. Through performance comparison between the proposed preprocessing method and the existing preprocessing method, it is shown that the proposed preprocessing method is a more effective method than the existing method in detecting potholes.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.65-71
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• 2011

This paper shows variations on bandwidth for the 5-microstrip 4-port structure by cutting out part of 2nd and 4th line of 5 lines. In 2nd line case, the bandwidth to pass is decreased by 300MHz and one of two input ports operates in diplexer. Both of 2nd and 4th line cut takes each of two input ports as a diplexer. The bandwidth for 4th line case has almost same bandwidth for the unmodified structure, a bit wider than that of the 2nd line case. Especially the isolation between input and other out port in center frequency of stop band shows 41dB for port 1, 32dB for port 2.

• The Journal of the Korea Contents Association
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• v.20 no.5
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• pp.271-280
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• 2020

The use of multiple celebrity endorsement is a common practice in advertising campaigns. However, little research has been conducted on the effects of multiple celebrity endorsement. In particular, the current study is designed to delve into what factors influence the effects of multiple celebrity endorsement. Portfolio-brand fit, portfolio-celebrity fit, and portfolio celebrity-consumer fit are three factors that affect a consumer's attitude toward the ad, the endorsed brand, and the purchase intention in the context of multiple celebrity endorsement. Study findings suggest that portfolio-brand fit, portfolio-celebrity fit, and portfolio celebrity-consumer fit positively affect attitudes toward the ad. In addition, as shown in the modified model, covariance among these three variables was found. Practical and theoretical implications were also discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1551-1556
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• 2012

This study proposes an efficient portfolio selection methodology for the listed corporations in KOSPI with consideration of managerial efficiency. For each industrial sector classified by KRX(Korea Exchange), the proposed method carries out an efficiency analysis using DEA (Data envelopment analysis) approach and for the efficient corporations filtered by DEA, construct portfolio using Markowitz's Model. In order to show the effectiveness of the proposed method, we constructed annually portfolios for 4 years (2007-2010) out of 600 listed corporations in KOSPI and KOSDAQ, and proved that our portfolios are superior to benchmark portfolios in terms of rate of returns.

• Education of Primary School Mathematics
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• v.15 no.3
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• pp.235-248
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• 2012

It has been a long time introduced portfolios as a new alternative assessment in the elementary school to make the wrong aspect of assessment into right aspect one in the traditional assessment. But many teachers seem to have not enough understanding of portfolios. Taking into account of this point of view, the purpose of this paper is to search what kind of suggestive points to give us and what is the fundamental difference with the portfolios we have already known by making an observation of consist of portfolios and cases carried out in new zealand elementary school.

• Korean Journal of Plant Resources
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• v.10 no.2
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• pp.165-168
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• 1997

To establish the culture practices for mass propagation of Epimedium koreanum, root propagules were preserved with different methods. Bud emergence rate and number of multiple buds were the highest in root segments obtained from roots with buds which were preserved in open-burial. Plant height, leaf area, and number of new buds were the highest in root segments obtained from roots preserved with stratification.