• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.1
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• pp.51-73
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• 2023

Social media play a significant role in communicating information across the globe, connecting with loved ones, getting the news, communicating ideas, etc. However, a group of people uses social media to spread fake information, which has a bad impact on society. Therefore, minimizing fake news and its detection are the two primary challenges that need to be addressed. This paper presents a multi-modal deep learning technique to address the above challenges. The proposed modal can use and process visual and textual features. Therefore, it has the ability to detect fake information from visual and textual data. We used EfficientNetB0 and a sentence transformer, respectively, for detecting counterfeit images and for textural learning. Feature embedding is performed at individual channels, whilst fusion is done at the last classification layer. The late fusion is applied intentionally to mitigate the noisy data that are generated by multi-modalities. Extensive experiments are conducted, and performance is evaluated against state-of-the-art methods. Three real-world benchmark datasets, such as MediaEval (Twitter), Weibo, and Fakeddit, are used for experimentation. Result reveals that the proposed modal outperformed the state-of-the-art methods and achieved an accuracy of 86.48%, 82.50%, and 88.80%, respectively, for MediaEval (Twitter), Weibo, and Fakeddit datasets.

• ETRI Journal
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• v.24 no.1
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• pp.56-64
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• 2002

This paper investigates how market participants react to mergers and acquisitions (M&As) involving telecommunications companies. The empirical evidence suggests that such activities convey bad news to the market. This is consistent with the synergy trap hypothesis and extant empirical findings of value-reducing diversification strategies in recent literature. The evidence also indicates that a cross-border, rather than a domestic M&A deal, is the main driver of the negative market reaction. Further, our evidence of negative impacts on the bidder's business after an M&A reinforces our main finding that market participants, on average, perceive M&A activities to be detrimental to shareholder value. This suggests that value creation or synergy through an M&A deal is not warranted even though it can generate an increase in size of the firm.

• Journal of Information Technology Applications and Management
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• v.17 no.3
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• pp.151-162
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• 2010

Recent developments in financial market liberalization and information technology are accelerating the interdependence of national stock markets. This study explores the information spillover effect of the US stock market on the overnight and daytime returns of the Korean stock market. We develop a profitable intra-day trading strategy based on the information spillover effect. Our study provides several important conclusions. First, an information spillover effect still exists from the overnight US stock market to the current Korean stock market. Second, Korean investors overreact to both good and bad news overnight from the US. Therefore, there are significant price reversals in the KOSPI 200 index futures prices from market open to market close. Third, the overreaction effect is different between weekdays and weekends. Finally, the suggested intra-day trading system based on the documented overreaction hypothesis is profitable.

• The Korean Journal of Financial Management
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• v.15 no.1
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• pp.73-94
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• 1998

This paper contributes to the ongoing controversy over price and volatility spillovers across countries by providing new evidence with the futures data of the S&P 500 and Nikkei 225 index futures contacts from January 3, 1990 to April 16, 1996. Based on the two-stage symmetric and asymmetric GARCH models we document that both the U.S. and the Japanese daytime returns significantly influence the subsequent overnight returns of the other market. We find no signs of volatility spillovers between two international markets with the symmetric model. However, with the asymmetric models, we find that the magnitude of foreign negative shocks are different from the positive ones. The findings generally suggest that the two markets are more sensitive to the bad news originating in the other market. This nature of transmission between two markets would have important implications to the arbitragers who are trying to exploit the short-term dynamics of price and volatility movements across two security markets.

• The Korean Journal of Financial Management
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• v.15 no.1
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• pp.183-205
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• 1998

공매(short sale)에 대한 제약이 없는 투자환경에 비해 공매에 대한 제약이 있는 투자환경에서는 주식과 같은 위험자산의 가격은 한동안 과대 평가된다. Figlewski & Webb (1993)는 공매에 대한 제약으로 인해 악재(bad news)가 주가에 과소 반영된다고 하였으며, Diamond & Verrecchia(1987)는 공매에 대한 여러 제약(short-sale constraints)으로 인해 주식시장에 호재로 작용하는 정보(favourable information)와 악재로 작용하는 정보(unfavourable information)가 주식시장에 비대칭적으로 반응하며, 악재가 주가에 더 늦게 반영된다는 것을 보였다. 그러나, 주가지수옵션의 거래는 여러 제약이 많은 공매제도로 인해 악재가 주식시장에 일시적으로 과소반영되는 비효율성을 해결해준다. 그래서 본 연구는 주가지수옵션이라는 파생금융상품의 도입으로 인해 악재의 주가 반응 속도에 어떠한 영향을 미치는 지에 대해 살펴보았다. 전환(switchig) GJR-MA(1) 모델을 이용한 실증분석 결과에 의하면, 주가지수옵션의 거래는 여러 제약이 많은 공매제도로 인해 악재가 주식시장에 늦게 반영되는 비효율성을 제거하게 되어, 옵션 도입 이후로 주식시장의 악재로 인한 변동성 충격(volatility shock)이 그 시장에 더욱 더 빨리 흡수되어 정보적 시장효율성(informational market efficiency)을 증대시키는 결과를 보였다.

• Asia-Pacific Journal of Business
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• v.12 no.1
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• pp.183-193
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• 2021

Purpose - The purpose of this study is to examine the impacts of global uncertainty on gross and net capital flows in Korea. Design/methodology/approach - We conduct an empirical analysis of the impact of global uncertainty on the net and gross capital flows in korea. To investigate the impacts, we incorporate linear and nonlinear ARDL models. Findings - We find global uncertainty has negative impacts on the gross and net capital flows. But this impact is nonlinear. The negative global uncertainty shocks are bigger than the positive global uncertainty shocks on capital flows in Korea. And we find this relationship is noticeable in gross capital inflows. We also find interest rate difference between the US and Korea is the main driving source in capital flow after the Global financial crisis. Research implications or Originality - The results of this study suggest that the negative impacts of global uncertainty are noticeable. This means that economic players in financial markets should be more concerned about the bad news.

• Korean journal of communication and information
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• v.39
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• pp.385-427
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• 2007

This study examined the primary tones of news stories and the overall frames which are structuralized by the primary tones in the news reporting of the Private School Law and social conflicts occurring around the law. For this purpose, the study applied Lakoff and Johnson's metaphoric conceptualization to the analysis of the news stories reported in the Chosun Ilbo, the Hankyoreh, and the Kookmin Ilbo, which are considered to represent the audience of the conservative, progressive, and religious forces, respectively. The main goal of this study includes to describe in which manner the newspapers attempt to depict the frames of major social conflicts regarding the Private School Law. The results show that (1) the Chosun Ilbo and the Kookmin Ilbo attempt to structuralize the social conflicts by providing frames of 'freedom is an asset' and a 'war' metaphors; (2) the Kookmin Ilbo applied more frames of a religious metaphor among others; and (3) the Hankyoreh attempts to structuralize the social conflicts by offering frames of 'the front is good, but the rear is bad' and 'war' metaphors, which proves to be the opposite in presenting the overall framing.

• Journal of Korea Port Economic Association
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• v.30 no.3
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• pp.1-14
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• 2014

This paper aims at measuring how new information is incorporated into volatility estimates. Various GARCH models are compared and estimated with daily BDI(Baltic Dry Index) data. While most researchers agree that volatility is predictable, they differ on how this volatility predictability should be modelled. This study, hence, introduces the asymmetric or leverage volatility models, in which good news and bad news have different predictability for future. We provide the systematic comparison of volatility models focusing on the asymmetric effect of news on volatility. Specifically, three diagnostic tests are provided: the sign bias test, the negative size bias test, and the positive size bias test. From the Ljung-Box test statistic for twelfth-order serial correlation for the level we do not find any significant serial correlation in the unpredictable BDI. The coefficients of skewness and kurtosis both indicate that the unpredictable BDI has a distribution which is skewed to the left and significantly flat tailed. Furthermore, the Ljung-Box test statistic for twelfth-order serial correlations in the squares strongly suggests the presence of time-varying volatility. The sign bias test, the negative size bias test, and the positive size bias test strongly indicate that large positive(negative) BDI shocks cause more volatility than small ones. This paper, also, shows that three leverage models have problems in capturing the correct impact of news on volatility and that negative shocks do not cause higher volatility than positive shocks. Specifically, the GARCH model successfully reveals the shape of the news impact curve and is a useful approach to modeling conditional heteroscedasticity of daily BDI.

• The Journal of Korean Association of Computer Education
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• v.12 no.2
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• pp.61-75
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• 2009

Modern day people can easily use an e-mail client for general communication, because of using Internet and cellular phone. The mail client for the purpose of private and business affair, advertisement, news searching, and business letter is widely used and has side effects. People could send an important document via an electronic mail client. It is important to support an e-mail client intelligent. We think that many kinds of techniques of natural language processing must be provided in the client with human's emotion. We consider to design a new mail client with six kinds of senders' emotional information; delight, angry, sad feeling and message to express, manner of talking, a discomfort index etc. Before sending an e-mail, we suggest a user to correct a bad word because we do not want to feel bad to a receiver. We present a proper process of sending/receiving for users with a new designed e-mail clients.

• Korean Business Review
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• v.20 no.2
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• pp.15-27
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• 2007

This paper analyzed the relationship between Housing Purchase Price volatility of Seoul and Housing Purchase Price volatility of local large city. Other studies investigates the effect on the observed volatility Observed volatility consists of fundamental volatility and transitory volatility. Fundamental volatility is caused by information arrival and transitory volatility is caused by noise trading. Fundamental volatility is trend component and is modelled as a random walk with drift. Transitory volatility is cyclical component and is modelled as a stationary process. In contrast to other studies, this study investigates the effect on the fundamental volatility and transitory volatility individually. Observed volatility is estimated by GJR GARCH(1,1) model. We find that GJH GARCH model is superior to GARCH model and good news is more remarkable effect on volatility than bad news. This study decomposes the observed volatility into fundamental volatility and transitory volatility using Kalman filtering method. The findings in this paper is as follows. The correlation between Seoul housing price volatility and Busan housing price volatility is high. But, the correlation between Seoul and Daejeon is low. And the correlation between Daejeon and Busan is low. As a distinguishing feature, the correlation between fundamental volatilities is high in the case of all pairs. But, the correlation between transitory volatilities turns out low. The reason is as follows. When economic information arrives, Seoul, Daejeon, and Busan housing markets, all together, are affected by this information.