• Journal of Intelligence and Information Systems
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• v.29 no.3
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• pp.1-17
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• 2023

With the recent rapid development of ICT(Information and Communication Technology) and the popularization of digital devices, the size of the online market continues to grow. As a result, we live in a flood of information. Thus, customers are facing information overload problems that require a lot of time and money to select products. Therefore, a personalized recommender system has become an essential methodology to address such issues. Collaborative Filtering(CF) is the most widely used recommender system. Traditional recommender systems mainly utilize quantitative data such as rating values, resulting in poor recommendation accuracy. Quantitative data cannot fully reflect the user's preference. To solve such a problem, studies that reflect qualitative data, such as review contents, are being actively conducted these days. To quantify user review contents, text mining was used in this study. The general CF consists of the following three steps: user-item matrix generation, Top-N neighborhood group search, and Top-K recommendation list generation. In this study, we propose a recommendation algorithm that applies an extended similarity measure, which utilize quantified review contents in addition to user rating values. After calculating review similarity by applying TF-IDF, Word2Vec, and Doc2Vec techniques to review content, extended similarity is created by combining user rating similarity and quantified review contents. To verify this, we used user ratings and review data from the e-commerce site Amazon's "Health and Personal Care". The proposed recommendation model using extended similarity measure showed superior performance to the traditional recommendation model using only user rating value-based similarity measure. In addition, among the various text mining techniques, the similarity obtained using the TF-IDF technique showed the best performance when used in the neighbor group search and recommendation list generation step.

• Proceedings of the Safety Management and Science Conference
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• 2004.11a
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• pp.355-380
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• 2004

I test the hypothesis that the gradual diffusion of information across asset markets leads to cross-asset return predictability in Korea. Using thirty-six industry portfolios and the broad market index as our test assets, I establish several key results. First, a number of industries such as semiconductor, electronics, metal, and petroleum lead the stock market by up to one month. In contrast, the market, which is widely followed, only leads a few industries. Importantly, an industry's ability to lead the market is correlated with its propensity to forecast various indicators of economic activity such as industrial production growth. Consistent with our hypothesis, these findings indicate that the market reacts with a delay to information in industry returns about its fundamentals because information diffuses only gradually across asset markets. Traditional theories of asset pricing assume that investors have unlimited information-processing capacity. However, this assumption does not hold for many traders, even the most sophisticated ones. Many economists recognize that investors are better characterized as being only boundedly rational(see Shiller(2000), Sims(2201)). Even from casual observation, few traders can pay attention to all sources of information much less understand their impact on the prices of assets that they trade. Indeed, a large literature in psychology documents the extent to which even attention is a precious cognitive resource(see, eg., Kahneman(1973), Nisbett and Ross(1980), Fiske and Taylor(1991)). A number of papers have explored the implications of limited information- processing capacity for asset prices. I will review this literature in Section II. For instance, Merton(1987) develops a static model of multiple stocks in which investors only have information about a limited number of stocks and only trade those that they have information about. Related models of limited market participation include brennan(1975) and Allen and Gale(1994). As a result, stocks that are less recognized by investors have a smaller investor base(neglected stocks) and trade at a greater discount because of limited risk sharing. More recently, Hong and Stein(1999) develop a dynamic model of a single asset in which information gradually diffuses across the investment public and investors are unable to perform the rational expectations trick of extracting information from prices. Hong and Stein(1999). My hypothesis is that the gradual diffusion of information across asset markets leads to cross-asset return predictability. This hypothesis relies on two key assumptions. The first is that valuable information that originates in one asset reaches investors in other markets only with a lag, i.e. news travels slowly across markets. The second assumption is that because of limited information-processing capacity, many (though not necessarily all) investors may not pay attention or be able to extract the information from the asset prices of markets that they do not participate in. These two assumptions taken together leads to cross-asset return predictability. My hypothesis would appear to be a very plausible one for a few reasons. To begin with, as pointed out by Merton(1987) and the subsequent literature on segmented markets and limited market participation, few investors trade all assets. Put another way, limited participation is a pervasive feature of financial markets. Indeed, even among equity money managers, there is specialization along industries such as sector or market timing funds. Some reasons for this limited market participation include tax, regulatory or liquidity constraints. More plausibly, investors have to specialize because they have their hands full trying to understand the markets that they do participate in

• Journal of the Korean Geographical Society
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• v.38 no.2
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• pp.312-323
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• 2003

This writer absolutely agrees with the government that regional disequilibrium is severe enough to consider moving the administrative capital. Pursuing this course solely to establish a balanced development, however, is not a convincing enough reason. The capital city is directly related to not only the social and economic situation but, much more importantly, to the domestic political situation as well. In the mid-1970s, the proposal by the Third Republic to move the capital city temporarily was based completely on security reasons. At e time, the then opposition leader Kim, Dae-jung said that establishing a safe distance from the demilitarized zone(DMZ) reflected a typically military decision. His view was that retaining the capital city close to the DMZ would show more consideration for the will of the people to defend their own country. In fact, independent Pakistan moved its capital city from Karachi to Islamabad, situated dose to Kashmir the subject of hot territorial dispute with India. It is regrettable that no consideration has been given to the urgent political situation in the Korean peninsula, which is presently enveloped in a dense nuclear fog. As a person requires health to pursue his/her dream, a country must have security to implement a balanced territorial development. According to current urban theories, the fate of a country depends on its major cities. A negligently guarded capital city runs the risk of becoming hostage and bringing ruin to the whole country. In this vein, North Koreas undoubted main target of attack in the armed communist reunification of Korea is Seoul. For the preservation of our state, therefore, it is only right that Seoul must be shielded to prevent becoming hostage to North Korea. The location of the US Armed Forces to the north of the capital city is based on the judgment that defense of Seoul is of absolute importance. At the same time, regardless of their different standpoints, South and North Korea agree that division of the Korean people into two separate countries is abnormal. Reunification, which so far has defied all predictions, may be realized earlier than anyone expects. The day of reunification seems to be the best day for the relocation of the capital city. Building a proper capital city would take at least twenty years, and a capital city cannot be dragged from one place to another. On the day of a free and democratic reunification, a national agreement will be reached naturally to find a nationally symbolic city as in Brazil or Australia. Even if security does not pose a problem, the governments way of thinking would not greatly contribute to the balanced development of the country. The Chungcheon region, which is earmarked as the new location of the capital city, has been the greatest beneficiary of its proximity to the capital region. Not being a disadvantaged region, locating the capital city there would not help alleviate regional disparity. If it is absolutely necessary to find a candidate region at present, considering security, balanced regional development and post-reunification scenario of the future, Cheolwon area located in the middle of the Korean peninsula may be a plausible choice. Even if the transfer of capital is delayed in consideration of the present political conflict between the South and the North Koreas, there is a definite shortcut to realizing a balanced regional development. It can be found not in the geographical dispersal of the central government, but in the decentralization of power to the provinces. If the government has surplus money to build a new symbolic capital city, it is only right that it should improve, for instance, the quality of drinking water which now everyone eschews, and to help the regional subway authority whose chronic deficit state resoled in a recent disastrous accident. And it is proper to time the transfer of capital city to coincide with that of the reunification of Korea whenever Providence intends.

• The Korean Journal of Air & Space Law and Policy
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• v.30 no.2
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• pp.83-153
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• 2015

As our economy grows and the number of aircraft increase, the number of civil execution against aircraft cases are likely to increase as well in the future. The purpose of this article is to present the legal theory on the civil execution against aircrafts by drawing on the legal theory on the civil execution against vessels which constitute a relatively large number of cases thus observed. The provisions of the civil execution against immovables or vessel, shall basically apply mutatis mutandis to the civil execution against aircraft or light aircraft. The civil execution against ultra-light flying devices or a foreign aircraft shall be executed in conformity with the civil execution against movables. There are a compulsory auction, an auction to execute a security right to aircraft, and an auction under the right of retention, etc. in the civil execution against an aircraft. A compulsory execution against an aircraft means an execution carried out by a creditor against a debtor's aircraft to obtain satisfaction of claims for the purpose of payment of money. The court of execution of a compulsory execution against an aircraft shall be the district court having jurisdiction over the airport of stoppage or storage of such aircraft at the time of seizure. The forums of execution of a compulsory execution against an aircraft shall be exclusive forums. When a court has rendered an order on commencing an auction, it shall order an execution officer to receive a certificate of the aircraft's registration and other documents as required for its operation, and to submit them to the court. A court may revoke the procedures for a compulsory auction when an execution officer fails to obtain a transfer of the aircraft's registration certificate, etc. and the location of the aircraft is not evident, not later than an elapse of 2 months from the date on which an order on commencing an auction has been rendered. In the case where it is deemed that there exists a business-related need or other based on proper reasoning, the court may permit the aircraft's operation, upon the motion submitted by the debtor. In this case, there shall be a consent from the creditor, the highest bidder, the next highest bidder and successful bidder. A court may, upon a motion submitted by the creditor, make the dispositions required for observing and preserving the aircraft. When a debtor has submitted the documents under subparagraph 2 or 4 of the Article 49 of the Civil Execution Act, and furnished the guarantee equivalent to the claims of the execution creditors and the creditors demanding a distribution and to the costs for execution, before a declaration of bid, the court shall, upon request, revoke other procedures than those for distribution. The provisions of a obligatory auction against vessel or aircraft and an auction to execute a security right to real estate or vessel, shall apply mutatis mutandis to an auction to execute the security right to aircraft. In an auction to execute the security right to aircraft case, an executive title is not necessary. An executory exemplification is not necessary in an application for an auction to execute the security right to aircraft. A court should examine the existence of security right and claim secured. No order on commencing an auction procedure shall be issued with non-existence or invalidity of the security right and absence or extinguishment of the claim secured. Furthermore, these prohibitions are the reason of a decision on non-permit for sale, the court overlooked these prohibitions, and the decision on a permit for sale became final and conclusive, the successful bidder who paid the price and registered of ownership could not acquire ownership of the aircraft sold. A court may render a ruling to put plural aircrafts up for a blanket auction, only when they are in restraint and related matter (Supreme Court Order 2001Ma3688 dated on August 22, 2001). A righter of retention on aircraft may file a request for an auction against the aircraft. The provisions of an auction to execute a security right to aircraft shall apply mutatis mutandis to the formal auction. Airport facility fee and an aircraft are not in restraint and related matter, so an airport management corporation does not hold the right of retention on the aircraft (Supreme Court Decision 2011Da29291 decided on April 10, 2014). In an auction in accordance with the right of retention, all encumbrances (e.g., mortgages) on the sold aircraft shall be extinguished by a sale under the legal conditions for sale. Not only creditors who have claims for preferential payment but also general creditors could demand for distribution. The precedence of the claim of the right of retention on aircraft and that of general creditor's claims are equal.