• Journal of the Economic Geographical Society of Korea
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• v.17 no.1
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• pp.98-113
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• 2014

The purpose of this study is to investigate the changes in the accessibility of the Metropolitan Seoul Transit systems since 2000, in which many new subway lines have been constructed as well as other urban transit lines have been connected to the systems. We suggest an accessibility measure model for Un-fixed Transportation Networks. In order to measure the nodal accessibility based on the mobility, we apply path-distance, physical-distance, and time-distance as the distance impedance measurement. Specifically, we develop time-distance algorithms to measure the time-distance between each pairs of transit stations based on the T-card transaction databases. We apply the model to the Metropolitan Seoul Transit systems in two time points(2005 and 2011). We examine the results in terms of three distance accessibility measures. Time-distance accessibility explains better the urban land use patterns in the Metropolitan Seoul area than the other two. We visualize the spatial patterns of time-distance accessibility by applying GIS, and analyze the spatial structures of accessibility in the Metrropolitan Seoul area between two time points.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.6
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• pp.1271-1283
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• 2019

The fourth industrial revolution and digital transformation are also bringing major changes to the financial ecosystem in Korea. Already, global financial firms overseas are opening their financial markets and exploring new financial businesses by seeking ways to co-prosperity with fintech firms. However, it is also true that the domestic financial environment has failed to respond to the changes due to its monopolistic and closed structure. In response, the government began pushing for the introduction of open banking in December 2019 with the aim of fully opening the financial settlement system. However, unlike the existing simple financial transaction structure, open banking still has an unresolved part due to the unclear relationship of responsibilities between interested parties in the event of financial accidents due to the complex linkage structure of transactions such as financial firms, fintech firms and customers. This study analyzed the security threat of open banking in depth. By doing so, the government and financial firms want to present policy proposals that need to be improved to enhance the safety of open banking in korea and protect financial consumers, as well as new financial models that have improved the vulnerable parts of existing models.

• Journal of KIISE:Software and Applications
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• v.34 no.7
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• pp.635-645
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• 2007

Component technology has been widely accepted as an effective way for building software systems with reusable components, and Microsoft (MS) .NET is one of the recent representative component technologies. Model Driven Architecture (MDA) is a new development paradigm which generates software by transforming design models automatically and incrementally. Transformation of structural models in MDA has been successfully applied. However, transformation of dynamic models and pervasive services, such as transaction service, security service, synchronization service and object pooling are largely remains as an area for further research. The recent enterprise system has multi tier distributed architecture, and the functionality of early mentioned pervasive services is essential for this architecture. .NET platform can implement Component Object Model+ (COM+) component for supporting pervasive services by specify Attribute code. In this paper, we specify the functionalities of the COM+ component offering pervasive services, and then those functionalities are defined by UML profile. By using the profile, the Platform Specific Model (PSM) for .NET/C# is specified, and .NET components are automatically generated through our tool. The development productivity, extensibility, portability, and maintenance of software can be dramatically improved by using of the proposed methods.

• Journal of KIISE:Software and Applications
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• v.30 no.11
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• pp.1025-1036
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• 2003

In industry, it is a current trend that systems are developed by using Enterprise JavaBeans(EJB) technology for reducing the cost and the time. Thus, the architecture of EJB is getting more essential to enhance reusability, extensibility and portability of system. However little has been studied in the realm of the practical software architectures for EJB. The architecture has just bean studied in abstract level, but not in concrete level providing the method to substantiate it using the practical J2EE techniques. Just using the EJB technology doesn't guarantee the reusability of the artifacts because EJB specification provides the characteristics and architecture for only fine grained components as session and entity bean. In this paper, we propose the enterprise software architecture for the systems based on EJB and the concrete techniques for implementing that. Also, design patterns of modeling efficient enterprise architecture are represented. By analyzing both the strengths and the weaknesses of suggested design patterns, EJB design patterns which are suitable for each layer of enterprise architecture will be identified. Through the component which design patterns are applied, the architecture can support the optimized relationship between the components. Five techniques for designing components from fine grained to coarse grained based on EJB technology, and architecture design techniques including transaction and assembling techniques are proposed.

• Journal of Korea Multimedia Society
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• v.5 no.4
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• pp.372-385
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• 2002

In this paper, we propose an efficient buffer replacement method for the real-time multimedia data. The proposed method has multi level priority to consider the real-time characteristics. Each priority level is divided into a cold data set that is likely to be referenced for the first time and a hot data set that is likely to be re-referenced. An operation to select the victim data is sequentially executed from the cold set with the minimum priority level to the hot set with the maximum Priority level. It is chosen only at the lower level than or equal to the priority of the transaction that requests a buffer allocation. In the cold set, our method selects a media that has the maximum size in the level for a target of victim first of all. And in the hot set, our method selects a medium that has the maximum interval of the reference first of all. Since it maintains many popular media in the limited buffer space, the buffer hit ratio is increased. It also manages many service requests. As a result, our method improves the overall performance of the system. We compare the proposed method with the Priority-Hints method in terms of the buffer hit ratio and the deadline missing ratio of transactions. It is shown through the performance evaluation that our method outperforms the existing methods.

• Journal of Cadastre & Land InformatiX
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• v.50 no.2
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• pp.133-153
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• 2020

Officially assessed land price has been the index of South Korea since 1989 throughout different sectors of tax and welfare. Officially assessed land price is used as a tax valuation for the tax on property holdings, and the equity of such is the most important factor in the fair taxation for the people of South Korea. On this wise, this research analyzed and verified the horizontal and vertical inequity of officially assessed land price in Seoul by using the real transaction data between 2016 and 2018. In fact, Seoul's assessment ratio for the entire three-year period was 60.64% and it showed to increase each year. Horizontal equity was found to be most favorable in 2017, and the horizontal equity of each borough of Seoul appeared to improve each year. Vertical inequity was found to have reverse inequality in most boroughs of Seoul, however, some parts of Gangnam districts such as Gangnam-gu, Seocho-gu, and Gangdong-gu presented progressive inequality. Such example showed the need for improvement in terms of balance by each borough. The use of quantile regression demonstrated reverse inequality in most quantile, but, the differences in the value of the coefficient by each quantile showed the need for improvement of officially assessed land price with the equity of each quantile. Through the equity verification of officially assessed land price, it was analyzed that the lack of equity was found by year, by borough, and by use district. In order to redeem the lack of equity, the government must systematically supplement the real-estate disclosure system by initiating ratio studies to verify horizontal and vertical equity.

• Korean Journal of Construction Engineering and Management
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• v.23 no.3
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• pp.74-82
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• 2022

With the introduction of proptech, this study aims to find out the changes and necessity of introducing blockchain technology, one of the most popular technologies, in real estate electronic transactions. In addition, it is intended to develop evaluation indicators that classify newly created values within real estate electronic transactions and calculate the relative importance of each value area through technology application. To this end, the value that can be created when applying blockchain technology to real estate electronic transactions was classified according to the hierarchy, and considering that the evaluation criteria are complex and the importance can be measured differently depending on various factors, an analysis was conducted according to the AHP method for experts in practical and academic fields. As a result of the analysis, general value showed the highest importance in the first dimension, and digitalization of real estate information showed the highest importance in the second dimension.

• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.147-155
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• 2022

In this study, we developed a system to dynamically balance a daily stock portfolio and performed trading simulations using gradient boosting and genetic algorithms. We collected various stock market data from stocks listed on the KOSPI and KOSDAQ markets, including investor-specific transaction data. Subsequently, we indexed the data as a preprocessing step, and used feature engineering to modify and generate variables for training. First, we experimentally compared the performance of three popular gradient boosting algorithms in terms of accuracy, precision, recall, and F1-score, including XGBoost, LightGBM, and CatBoost. Based on the results, in a second experiment, we used a LightGBM model trained on the collected data along with genetic algorithms to predict and select stocks with a high daily probability of profit. We also conducted simulations of trading during the period of the testing data to analyze the performance of the proposed approach compared with the KOSPI and KOSDAQ indices in terms of the CAGR (Compound Annual Growth Rate), MDD (Maximum Draw Down), Sharpe ratio, and volatility. The results showed that the proposed strategies outperformed those employed by the Korean stock market in terms of all performance metrics. Moreover, our proposed LightGBM model with a genetic algorithm exhibited competitive performance in predicting stock price movements.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.1
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• pp.129-141
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• 2024

Amidst the acceleration of digital transformation across various sectors, the financial market is increasingly focusing on the development of digital and electronic payment methods, including currency. Among these, Central Bank Digital Currencies (CBDC) are emerging as future digital currencies that could replace physical cash. They are stable, not subject to value fluctuation, and can be exchanged one-to-one with existing physical currencies. Recently, both domestic and international efforts are underway in researching and developing CBDCs. However, current CBDC systems face scalability issues such as delays in processing large transactions, response times, and network congestion. To build a universal CBDC system, it is crucial to resolve these scalability issues, including the low throughput and network overload problems inherent in existing blockchain technologies. Therefore, this study proposes a solution based on reinforcement learning for handling large-scale data in a CBDC environment, aiming to improve throughput and reduce network congestion. The proposed technology can increase throughput by more than 64 times and reduce network congestion by over 20% compared to existing systems.

• Journal of Distribution Research
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• v.15 no.5
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• pp.217-235
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• 2010

In franchise industry, territorial restraint is a system that imposes exclusive right to franchisers in a certain business area. To the franchisers, this system guarantees monopoly profits in a local market and exclusive rights during the contract periods. In such a way, franchisee generates a big revenue at once on the basis of franchiser's initial investment such as interior cost and franchise fee, it must have supervised franchiser's moral hazard for the territorial restraint agreement. Rather than territorial restraint can be a system to give exclusive right to franchiser's so that they neglect their own sales and too much rely on headquarter's brand and marketing activities without their own efforts. This paper assesses the implication of territorial restraint by examining the effect on brand extension, degree of contract termination. Drawing on research in transaction cost agreement and opportunism, the authors suggest that franchisee is highly likely to launch similar brand which is not effected on previous contract when territorial restraint is set out in the contract system. Moreover, the authors find that the degree of contract termination will be high in the existence of territorial restraint due to the franchisee's opportunism. The results imply that territorial restraint induces franchisee's opportunistic strategy more aggressively so that the possibility of brand extension or new brand launching will be increased. At the same time, franchisee is aggressively seeking for the reason for contract termination due to the pursuit of its profit maximization. Based on some empirical findings, this paper concludes with policy implications and some necessary fields of future studies desirable.