• KIEE International Transaction on Systems and Control
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• v.2D no.2
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• pp.92-96
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• 2002

This paper is concerned with properties of a Lyapunov functional of state delay systems. It is shown that if a state delay system has a pure imaginary pole for some state delay, then no Lyapunov functional satisfying a Lyapunov condition exists periodically with respect to change of the state delay. This periodic property is unique in state delay systems and has been well known in the frequency domain stability conditions. However, in the time domain stability conditions using a Lyapunov functional, the periodic property is not known explicitly.

• KIEE International Transaction on Systems and Control
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• v.12D no.1
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• pp.43-50
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• 2002

In the recent years neural networks have fulfilled the promise of providing model-free learning controllers for nonlinear systems; however, it is very difficult to guarantee the stability and robustness of neural network control systems. This paper proposes an adaptive neural network control for robot manipulators based on the radial basis function netwo.k (RBFN). The RBFN is a branch of the neural networks and is mathematically tractable. So we adopt the RBFN to approximate nonlinear robot dynamics. The RBFN generates control input signals based on the Lyapunov stability that is often used in the conventional control schemes. The saturation function is also chosen as an auxiliary controller to guarantee the stability and robustness of the control system under the external disturbances and modeling uncertainties.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.11
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• pp.471-478
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• 2014

Database replication is utilized to increase credibility, availability and prevent overload of distributed databases. Two models currently exist for replication - Master/Slave and Multi-Master. Since the Multi-Master model has problems of increasing complexity and costs to interface among multiple databases for updates and inserts, the Master/Slave model is more appropriate when frequent data inserts and updates are required. However, Master/Slave model also has a problem of not having exact criteria when systems choose to connect between Master and Slave for transactions. Therefore, this research suggests a routing algorithm based on AOP (Aspect Oriented Programming) in the Master/Slave database model. The algorithm classifies applications as cross-cutting concerns based on AOP, modularizes each concern, and routes transactions among Master and Slave databases. This paper evaluates stability and performance of the suggested algorithm through integration tests based on scenarios.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.22
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• pp.173-197
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• 2004

Letter of Credit between buyer and seller in International Trade Transaction is the means of payment which makes International Trade operate smoothly by guaranteeing an exporter against non-payment and an importer against non-delivery. Therefore, the parties to a sale apply UCP500 established by the International Chamber of Commerce, in accordance with principle of the freedom of contract among the parties concerned, to look to their own legal stability. However, we may recognize some cases to have been applied principle of faith and trust, one of the dominant principles of the civil law, by the Korean Supreme Court and other cases to have not been applied that principle by the Korean Supreme Court. The Court shall apply UCP500 strictly as long as the parties concerned adopt UCP500 in view of the legal stability. In other words, in case that the Court applies principle of faith and trust to the case related to L/C, this rule - principle of faith and trust - should apply to the subject matter which have not stipulated in UCP500 under certain restriction. We suggest keeping in mind points to korean companies as follows; First, the parties to a sale shall understand L/C basis transaction and principles related to L/C deeply. Second, the exporter shall prepare documents in compliance with L/C and fulfil his or her obligation according to UCP500 and L/C related to the contract. Third, as buyer or importer, when he or she receive the shipping documents with discrepancies from the notifying bank, he or she makes him or herself clear to all the parties concerned. Fourth, as bank, she shall examine all the documents according to UCP500 and L/C related to the contract, and if any document with discrepancies, the bank, by all means, shall approach applicant first, and then decide whether to pay the credit amount to beneficiary or not to.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.3
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• pp.1-9
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• 2017

Recently, Bitcoin which is digital currency and cryptocurrency is getting worldwide attention since Bitcoin has an ability to replace legal tender unlike other existing cyber currency. Especially, most Bitcoin trading is done between two traders such as P2P method and it does not require a third-party to make sure reliability and it records every transaction details, so it is more transparent then traditional financial trade, so the number of users is increasing. However, Bitcoin, which has been recognized for transparency, confidentiality and stability among traders has recently been threatened by illegal transactions such as money laundering and the attack on the exchange. These threats to Bitcoin are becoming social problems. At first, it seems that most of the digital currency is difficult to get hacked due to the Blockchain technology. However, threats such as digital money leaks by user account hacking and paralyzing the servers are increasing. In this paper, it will examine the features of the Bitcoin and the threatening elements to secure marketability of digital currency such as Bitcoin and receive more interest from public in domestic. The paper will examine the problems of Blockchain technology on speculative transactions and fraudulent behavior by analyzing the problems of Bitcoin transaction. Lastly, it will propose ways to make transparent and secure digital currency transactions.

• International Commerce and Information Review
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• v.9 no.3
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• pp.59-79
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• 2007

This paper is to identify whether the mechanism of the real market as an off-line market developed from the transaction cost theory from previous research is applied to on-line market, such as usiness to Business e-marketplaces. With three factors(parties, product, environments) selected from previous research, four cases picked up from all B2B e-marketplace sites as of April 2007, in the view of Business to Business Matrix which presented by Kaplan & Sawhney(2000), were studied. They were accompanied by interview with CEO and team manager, and they explained their business and revenue model of the company. From the interview, the relation between three factors and usiness to Business e-marketplace was observed by taking sub-factors into consideration; parties -asset specificity, information asymmetry, product factors - standardization, price stability, and environments factors - competition, market uncertainty. The implications of this study are to analyze the relation of the transaction theory in offline and online. Also, this is the first study that analyzed it. In the future, another research based on this research will be studied.

• Journal of Information Processing Systems
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• v.16 no.3
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• pp.699-717
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• 2020

Propagation time on permissionless blockchain plays a significant role in terms of stability and performance in the decentralized systems. A large number of activities are disseminated to the whole nodes in the decentralized peer-to-peer network, thus causing propagation delay. The stability of the system is our concern in the first place. The propagation delay opens up opportunities for attackers to apply their protocol. Either by accelerating or decelerating the propagation time directly without proper calculation, it brings numerous negative impacts to the entire blockchain system. In this paper, we thoroughly review and elaborate on several parameters related to the propagation time in such a system. We describe our findings in terms of data communication, transaction propagation, and the possibility of an interference attack that caused an extra propagation time. Furthermore, we present the influence of block size, consensus, and blockchain scalability, including the relation of parameters. In the last session, we remark several points associated with the propagation time and use cases to avoid dilemmas in the light of the experiments and literary works.

• Economic Analysis
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• v.26 no.2
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• pp.1-42
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• 2020

This paper studies, from a quantity theory of money perspective, the reasons that North Korean inflation and exchange rates maintain stability while its economy is experiencing difficulties due to the international community's economic sanctions. In doing so, this paper uses both domestic and foreign currencies in an analytic model based on the quantity theory of money to cautiously reflect North Korea's dollarization as well as its management of its exchange rate. In particular, foreign currency holdings are divided into those for store-of-value purposes and those for transaction purposes. This paper shows that in the early stages, in which the amount of foreign currency holdings for store-of-value purposes is decreasing while the amount of foreign currency holdings for transaction purposes is intact, inflation and exchange rates both exhibit stable movements. In the middle stages, where the amount of foreign currency holdings for transaction purposes begins to fall, exchange rates show some increase and inflation decreases. In the final stages, when the amount of foreign currency holdings for transaction purposes significantly decreases, exchange rates and inflation both increase, and in some situations a crisis can happen. According to this paper's analysis, if the economic sanctions continue to the extent that the amount of North Korean foreign currency holdings for transaction purposes starts to fall, the exchange rate and inflation stability we see now are unlikely to be maintained.

• Journal of Digital Convergence
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• v.19 no.2
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• pp.151-160
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• 2021

The purpose of this study is to classify online shopping malls into total transaction amount and transaction amount by product, and compare them to find synchronism. The data used in this study were collected from KOSIS for Food Services, Home Appliances·Electronics·Communication devices, Food & Beverages, House_Goods, Clothing, Computers & Peripheral Devices. The analysis period is a total of 44 monthly data from January 2017 to August 2020. In descriptive statistics, variability is relatively very stable in the case of food service, but is large in the case of clothing. In the correlation analysis, the total transaction amount shows a certain level of correlation with each product. In the analysis of the increase rate, Food Service increased by 1,039%, Home Appliances·Electronics·Communication devices increased by 325%, Food & Beverages increased by 296% and House Goods by 250%, but Clothing decreased slightly to 92.56%. In the Scatter Charts analysis, the distribution of Total transaction amount & House Goods, Total transaction amount & Home Appliances·Electronics·Communication devices is generally upward, showing a high level of synchronization. Due to Corona 19, we will have to continue our efforts to provide speed, stability, convenience and various services in preparation for the increase in transaction volume of online shopping malls.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4786-4793
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• 2012

In a recent mobile computing environment, the research for a transaction model have been actively carried out to deal with real-time transaction. However, the research for recovery model is relatively insufficient. Therefore, it would be very important for mobile recovery methods for database stability, just in case of data loss due to hand-off in mobile computing system. So, further efficient research should be keenly done to reduce I/O hand-off in mobile computing systems. SLL method increases I/O time due to sequential file. This paper have been suggested to efficient mobile recovery method in mobile computing system. Finally, it has been clearly demonstrated for system efficiency, conducting the performance assessment that currently proposed recovery system.