• Journal of Intelligence and Information Systems
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• v.9 no.3
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• pp.1-21
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• 2003

In this research, we developed a Multi-Agent based Negotiation Support System to be able to increase the competitive power of a company in dynamic environment and correspond to various orders of customers by diffusion of electronic commerce. The system uses the agent technology that is being embossed as new paradigm in dynamic environment and flexible system framework. The multi-agent technology is used to solve these problems through cooperation of agent. The system consists of six sub agents: Mediator, manufacturability Analysis Agent, Process Planning Agent, Scheduling Agent, Selection Agent, Negotiation-strategy Building Agent. In this paper, the proposed Multi-Agent based Negotiation Support System takes aim at the automation of transaction process from ordering to manufacturing plan through the automation of negotiation that is the most important in order-taking transaction.

• Journal of Korea Multimedia Society
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• v.7 no.5
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• pp.633-639
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• 2004

The performance of optimistic concurrency control schemes which are generally used for Mobile computing is very sensitive to the transaction abort rate. Even if the abort probability can be reduced by back-shifting the timestamp from the time of requesting a commit, some transactions continuously perform unnecessary operations after the transactions accessed write-write conflicting data. In this paper, we propose an optimistic protocol that can abort the transactions during the execution phase by using the write notification approach. The proposed protocol enhances the performance of the optimistic concurrency control by reducing the unnecessary operations. In addition, we present a simulation study that compares our schemes with the timestamp based certification scheme. This study shows that our scheme outperforms the timestamp based certification scheme.

• Journal of the Korea Society of Computer and Information
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• v.20 no.1
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• pp.143-151
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• 2015

Biometric technology has been proposed as a new means to replace conventional PIN or password because it is hard to be lost and has the low possibility of illegal use. However, unlike a PIN, password, and personal information there is no way to modify the exposure if it is exposed and used illegally. Therefore, the existing single modality with single biometrics is critical when it expose. However in this paper, we use a multi-modality and multi-biometrics to authenticate between users and TTP or between users and financial institutions. Thereby, we propose a more reliable method and compared this paper with existed methods about security and performance in this paper.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.4
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• pp.715-729
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• 2021

Bitcoin is one of the cryptocurrencies, which is decentralized and transparent. However, due to its anonymity, it is currently being used for the purpose of transferring funds for illegal transactions in darknet markets. To solve this problem, clustering heuristic based on the characteristics of a Bitcoin transaction has been proposed. However, we found that the previous heuristis suffer from high false negative rates. In this study, we propose a novel heuristic for bitcoin clustering using off-chain data. Specifically, we collected and analyzed user review data from Silk Road 4 as off-chain data. As a result, 31.68% of the review data matched the actual Bitcoin transaction, and false negatives were reduced by 91.7% in the proposed method.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.1189-1200
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• 2021

This study examines the role of perceived enjoyment, self-efficacy, and subjective norms as determinants of behavioral intention to use the OVO application. This study's target population is the users of the OVO application who have used it as an electronic transaction. This study's population was the OVO application users as an electronic transaction tool in Jember Regency. Samples were randomly selected at the time of the survey with specific criteria. The survey location is determined at the Plaza because it is a shopping center that mostly has payments at OVO partner merchants. The model empirically tested using data gathered from 150 respondents of OVO users. The research model was tested by using the structural equation modeling (SEM) approach. The results showed that all constructs in the original TAM model were statistically significant. Subjective norm has a positive effect on perceived usefulness, and perceived enjoyment positively affects perceived ease of use of OVO applications. On the other hand, applications' self-efficacy does not affect the perceived ease of using OVO applications for electronic transactions. This condition shows that subjective norms are dominant external individual perspectives compared to self-efficacy, which are personal internal characteristics in determining the behavioral intention of using OVO applications in electronic transactions.

• Current Optics and Photonics
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• v.6 no.6
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• pp.565-575
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• 2022

In this paper, we propose a non-fungible token (NFT) transaction method that can commercialize the real 3D property and make property sharing possible using the 3D reconstruction technique. In addition, our proposed method enhances the security of NFT copyright and metadata by using optical encryption. In general, a conventional NFT is used for 2D image proprietorial rights. To expand the scope of the use of tokens, many cryptocurrency industries are currently trying to apply tokens to real three-dimensional (3D) property. However, many token markets have an art copyright problem. Many tokens have been minted without considering copyrights. Therefore, tokenizing real property can cause significant social issues. In addition, there are not enough methods to mint 3D real property for NFT commercialization and sharing property tokens. Therefore, we propose a new token management technique to solve these problems using integral imaging and double random phase encryption. To show our system, we conduct a private NFT market using a test blockchain network that can demonstrate the whole NFT transaction process.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.361-372
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• 2021

This research aimed to analyze the momentum strategy of foreign investors with the smallest trading transactions in the Indonesian stock market. This study applied a quantitative method approach using intraday transaction data of companies listed on the LQ-45 Index for March, April, and May 2017, obtained from the Indonesia Capital Market Institute (TICMI) which is a subsidiary of the Indonesia Stock Exchange (IDX). The number of companies with available data is 35 companies, consisting of 23 non-government stocks and 12 government stocks. The number of observations from the 35 companies was 8,686,030 observations where the government companies recorded 2,751, 545 and the non-government companies 1,387,016 observations. All data was then squeezed and grouped into small, medium, and large trade transaction orders. The data analysis method used was paired t-test with SPSS to analyze cumulative abnormal returns in the formulation and test periods. This study found that small foreign investors carried out momentum strategies on stocks listed on the LQ-45 Index. However, re-testing was done by separating government and non-government shares. It turned out that small foreign investors performed a momentum strategy on non-government and a contrarian strategy on government.

• International Journal of Computer Science & Network Security
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• v.23 no.5
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• pp.128-134
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• 2023

The widespread usage of blockchain technology in cryptocurrencies has led to the adoption of the blockchain concept in data storage management systems for secure and effective data storage and management. Several innovative studies have proposed solutions that integrate blockchain with distributed databases. In this article, we review current blockchain databases, then focus on two well-known blockchain databases-BigchainDB and FalconDB-to illustrate their architecture and design aspects in more detail. BigchainDB is a distributed database that integrates blockchain properties to enhance immutability and decentralization as well as a high transaction rate, low latency, and accurate queries. Its architecture consists of three layers: the transaction layer, consensus layer, and data model layer. FalconDB, on the other hand, is a shared database that allows multiple clients to collaborate on the database securely and efficiently, even if they have limited resources. It has two layers: the authentication layer and the consensus layer, which are used with client requests and results. Finally, a comparison is made between the two blockchain databases, revealing that they share some characteristics such as immutability, low latency, permission, horizontal scalability, decentralization, and the same consensus protocol. However, they vary in terms of database type, concurrency mechanism, replication model, cost, and the usage of smart contracts.

• Asian Journal of Business Environment
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• v.12 no.1
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• pp.25-33
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• 2022

Purpose: The purpose of this paper is to determine the effects of the Real Estate Transactions Tax (RETT) on the economic cycles of Saudi Arabia. A secondary purpose is to determine the effects of RETT on the construction and real estate sectors of Saudi Arabia. Research design, data and methodology: The data used is retrieved from the General Authority of Statistics, Saudi Central Bank and the World Bank Open Data. Econometric models of multiple linear regression with dummy variables have been conducted to achieve the objectives and to quantitatively verify the hypotheses. Results: With the VAT exemption in real estate transactions and its substitution with RETT, a positive effect on the economy and the real estate sector has been observed. However, this tax reform has not produced any significant effects in the construction sector. Conclusions: The main conclusion of the present research is that the real estate market has a major influence on economic cycles. After the tax reform, a reduction in the contribution of taxes on real estate transactions to GDP was detected. For the construction sector, after the tax reform, it is estimated that there will be an insignificant reduction in the contribution of the real estate price index, and of the taxes on real estate transactions, to GDP.

• Korea Trade Review
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• v.47 no.2
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• pp.103-120
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• 2022

This paper studies the possibility of options as an instrument for central bank to intervene foreign exchange market. As opposed to spot transaction or forward transaction, which impacts spot exchange rate only once, currency options can continuously resist a directional speculative pressure on spot market due to the dynamic delta hedging of OTC currency options market maker. This research also analyzes whether and how central banks can use currency options to lower exchange rate volatility and maintain (implicit) target zones in foreign exchange markets. It argues that short position rather than long position in options will result in market makers dynamically hedging their long option exposure in a stabilizing manner, consistent with the first objective. Selling a "Strangle" allows a central bank to increase the credibility of its commitment to a target zone, and could have a lower expected cost than spot market interventions. However, this strategy also exposes the central bank to an unlimited loss potential. Therefore these kinds of intervention strategies must be used in the short run and temporarily.