• KDI Journal of Economic Policy
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• v.25 no.2
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• pp.137-170
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• 2003

Despite the great success of the derivatives market, several concerns were expressed regarding the additional volatilitystemming from program trading during the expiration of derivatives. This paper examines the impact of the expiration of the KOSPI 200 index derivatives on cash market of Korea Stock Exchange(KSE). The KOSPI 200 index derivatives market has a unique settlement price determination process. The settlement price for the expiration of derivatives is determined by call auction during the last 10 minutes after the trades for matured derivatives are finalized. We analyze typical expiration day effects such as price, volatility, and volume effects. With high frequency data, we find that there are strong expiration day effects in the KSE and try to interpret the results with the unique settlement procedures of the KOSPI 200 cash and derivatives markets.

• Information Systems Review
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• v.13 no.3
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• pp.123-139
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• 2011

This paper researches the value of domestic telecommunication bundle products. Customers evaluate each telecommunication products differently according to their attributes. The attributes affecting the customer value of telecommunication bundling can be categorized in 3 ones as follows; corporate image, service feature, and service price. Also authors analyze the difference of importancy that customers consider when they evaluate each products, and propose the optimal scenario for bundling. In conclusion, other two companies A, C excluding B should invest more resources into the portion that strengthen the attributes of company image, and service feature to upgrade their 'corporate image', and 'service feature'. According to 6-scenarios analysis on the bundle products, the QPS expansion of company A was the most advantageous position, but if companies B, C expand DPS made use of their strengths, they can prevent from decreasing additivity rapidly with sequential scenario. The above results show that one company may have equable power in each area, but if another company having strengths in special areas makes up for its weakness and differentiates gradually it can contribute to strengthen its competitiveness. This contributed much more theoretical and practical than the existing researches. Supposing that additivity index evaluated by consumers can be changed by efforts of companies, this scenario planning is the result of study showing that the investment and publicity of each company have to be considered as its characteristic of each product at the same time.

• Korean journal of communication and information
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• v.49
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• pp.39-56
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• 2010

This study on the exposed the viewers diversity as a basic cable television service. Diversity is the most basic goal of broadcasting policy has important implications. But still, such as cable and pay-media research on the viewing diversity has made a limited basis. SO much to offer for the cable offers viewers receive the number of channels available to compare the diversity of the field was verified. Price rises of analysis for the cable the more the number of channels offered to supply the channel has increased the diversity of the field. SO granted in accordance with the results of a market strategy, but for a variety of channels to be provided by a policy perspective, the price depending on the choice of a variety of audiences can be quite limited means. That is a wide range of viewers watching the channel had a right to be limited. These phenomena to improve the pay television service and the need to manage the Product channel diversity index was raised.

• The Journal of the Korea Contents Association
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• v.20 no.2
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• pp.96-104
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• 2020

As consumers' consumption activities become more active due to the activation of online shopping malls, companies are conducting item trend analyses to boost sales. The existing item trend analysis methods are analyzed by considering only the activities of users in online shopping mall services, making it difficult to identify trends for new items without purchasing history. In this paper, we propose a trend analysis method that combines data in online shopping mall services and social network data to analyze item trends in users and potential customers in shopping malls. The proposed method uses the user's activity logs for in-service data and utilizes hot topics through word set extraction from social network data set to reflect potential users' interests. Finally, the item trend change is detected over time by utilizing the item index and the number of mentions in the social network. We show the superiority of the proposed method through performance evaluations using social network data.

• International Area Studies Review
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• v.16 no.3
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• pp.239-266
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• 2012

The purpose of this paper is to suggest desirable improvement for KRX derivatives market plagued with many problems in spite of its world level of quantitative growth. In order to try to find desirable improvement for KRX derivatives market which has many problems like that, I suggest various ways of improvement for regulatory system in the future in terms of behavioral regulation for investor protection. First of all, in order to relieve speculative tendency of trading, KOSPI200 option market with ATM-oriented option trading needs to be induced from the market in which OTM-oriented option is now trading. So discount or exemption of brokerage fee for ATM trading and the introduction of market-maker for ATM type can be considered. For the protection of individual investors, we suggest feasible plans such as differential regulation between professional and individual investors, consolidation of basic deposit management, and enlargement of opportunities for risk management education & simulation trading.

• Journal of Intelligence and Information Systems
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• v.23 no.3
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• pp.29-44
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• 2017

In Internet commerce, consumers are heavily influenced by product reviews written by other users who have already purchased the product. However, as the product reviews accumulate, it takes a lot of time and effort for consumers to individually check the massive number of product reviews. Moreover, product reviews that are written carelessly actually inconvenience consumers. Thus many online vendors provide mechanisms to identify reviews that customers perceive as most helpful (Cao et al. 2011; Mudambi and Schuff 2010). For example, some online retailers, such as Amazon.com and TripAdvisor, allow users to rate the helpfulness of each review, and use this feedback information to rank and re-order them. However, many reviews have only a few feedbacks or no feedback at all, thus making it hard to identify their helpfulness. Also, it takes time to accumulate feedbacks, thus the newly authored reviews do not have enough ones. For example, only 20% of the reviews in Amazon Review Dataset (Mcauley and Leskovec, 2013) have more than 5 reviews (Yan et al, 2014). The purpose of this study is to analyze the factors affecting the usefulness of online product reviews and to derive a forecasting model that selectively provides product reviews that can be helpful to consumers. In order to do this, we extracted the various linguistic, psychological, and perceptual elements included in product reviews by using text-mining techniques and identifying the determinants among these elements that affect the usability of product reviews. In particular, considering that the characteristics of the product reviews and determinants of usability for apparel products (which are experiential products) and electronic products (which are search goods) can differ, the characteristics of the product reviews were compared within each product group and the determinants were established for each. This study used 7,498 apparel product reviews and 106,962 electronic product reviews from Amazon.com. In order to understand a review text, we first extract linguistic and psychological characteristics from review texts such as a word count, the level of emotional tone and analytical thinking embedded in review text using widely adopted text analysis software LIWC (Linguistic Inquiry and Word Count). After then, we explore the descriptive statistics of review text for each category and statistically compare their differences using t-test. Lastly, we regression analysis using the data mining software RapidMiner to find out determinant factors. As a result of comparing and analyzing product review characteristics of electronic products and apparel products, it was found that reviewers used more words as well as longer sentences when writing product reviews for electronic products. As for the content characteristics of the product reviews, it was found that these reviews included many analytic words, carried more clout, and related to the cognitive processes (CogProc) more so than the apparel product reviews, in addition to including many words expressing negative emotions (NegEmo). On the other hand, the apparel product reviews included more personal, authentic, positive emotions (PosEmo) and perceptual processes (Percept) compared to the electronic product reviews. Next, we analyzed the determinants toward the usefulness of the product reviews between the two product groups. As a result, it was found that product reviews with high product ratings from reviewers in both product groups that were perceived as being useful contained a larger number of total words, many expressions involving perceptual processes, and fewer negative emotions. In addition, apparel product reviews with a large number of comparative expressions, a low expertise index, and concise content with fewer words in each sentence were perceived to be useful. In the case of electronic product reviews, those that were analytical with a high expertise index, along with containing many authentic expressions, cognitive processes, and positive emotions (PosEmo) were perceived to be useful. These findings are expected to help consumers effectively identify useful product reviews in the future.

• 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.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.939-940
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• 2009

글로벌 무한경쟁에서 고객들의 품질평가 결과가 반영된 고객만족지수가 높은 제품들이 시장에서 호평을 받고 판매가 확대되는지 자동차와 IT분야의 휴대폰을 대상으로 분석하였다. 실증분석결과로써 장기수명 내구재인 자동차는 높은 상관성을 유지하였으나 짧은수명 내구재인 휴대폰 분야는 높은 고객 만족지수를 획득하였어도 높은 시장점유율로 연결되지는 않았다. 본연구결과는 시장조사 및 상품기획의 마케팅분야와 내구품질 즉 신뢰성분야에서 유용한 시사점을 제공하는데 의의가 있다.

• The Journal of the Korea Contents Association
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• v.21 no.12
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• pp.34-46
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• 2021

In the domestic data exchanging market, unreasonable pricing of purchase data is consistently mentioned as a major obstacle in data trading. This is a problem caused by the inability to properly evaluate the value of data products due to lack of product information and experience in using them. In order to activate trading, the data exchanges need to provide information that allows consumers to comprehensively judge the value of data products in addition to prices. The cost-based, income-based, and market-based methods, which are mainly applied to data valuation, are insufficient as data valuation methods to stimulate trading and distribution because only price information, a result of valuation from a supplier's point of view, can be shared with consumers. This study aims to develop a measurable valuation method that allows data trading stakeholders (exchanges, suppliers, and consumers) to judge and share the value of data products from a common perspective. To this end, we identified the value drivers of data products, which are considered important in overseas data exchanges and related research, and derived an evaluation method that can quantitatively measure each value driver. In addition, evaluation criteria in the form of a rating table were developed using data products for transactions, and a value evaluation index was developed through stratification analysis (AHP) to enable relative value comparison. As a result of applying the evaluation criteria to actual data products, it was found that the evaluation values were differentiated according to the characteristics of individual data products, so it could be used as a relative value comparison tool.

• Communications for Statistical Applications and Methods
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• v.17 no.3
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• pp.459-471
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• 2010

Higher quality level is generally perceived by customers as improved performance by assigning a correspondingly higher satisfaction score. Usually, the quality level is measured by process capability indices. The index is used to determine whether a production process is capable of producing items within a specified tolerance. The third generation index $C_{pmk}$ is more powerful than two useful indices $C_p$ and $C_{pk}$. which have been widely used in six sigma industries to assess process performance. Most evaluations on process capability indices focus on point estimates, which may result in unreliable assessments of process performance. In this paper, we consider better testing procedure on assessing process capability index $C_{pmk}$ for practitioners to use in determining whether a given process is capable. It is easy to use the proposed method for assessing process capability index $C_{pmk}$. Whether a process is clearly normal or nonnormal, our bootstrap testing procedure could be applied effectively without the complexity of calculation. A numerical result based on our proposed method is illustrated.