• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.1
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• pp.455-472
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• 2020

As a user in modern societies with the rapid growth of Internet environment and more complicated business flow processes in order to be effective at work and accomplish things on time when the manager of the company went for a business trip, he/she need to delegate his/her signing authorities to someone such that, the delegatee can act as a manager and sign a message on his/her behalf. In order to make the delegation process more secure and authentic, we proposed a secure and efficient identity-based proxy signcryption in cloud data sharing (SE-IDPSC-CS), which provides a secure privilege delegation mechanism for a person to delegate his/her signcryption privilege to his/her proxy agent. Our scheme allows the manager of the company to delegate his/her signcryption privilege to his/her proxy agent and the proxy agent can act as a manager and generate signcrypted messages on his/her behalf using special information called "proxy key". Then, the proxy agent uploads the signcrypted ciphertext to a cloud service provider (CSP) which can only be downloaded, decrypted and verified by an authorized user at any time from any place through the Internet. Finally, the security analysis and experiment result determine that the proposed scheme outperforms previous works in terms of functionalities and computational time.

• Journal of Advanced Navigation Technology
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• v.13 no.3
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• pp.393-398
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• 2009

In this paper, we study the design and implementation of an auto recognition system by using wireless sensor node. RFID system has a limited communication range and communication network is damaged, it is impossible to communicate. Therefore, easy installation and low cost wireless system are required in an area where the installation of communication between RFID system and monitoring system is difficult, or a portable RFID system is installed. The auto recognition system in this study is implemented by the combination of 13.56MHz RFID system using MLX12115 RFID chip of Melexis company and wireless sensor node system using CC2420 Zigbee chip of Chipcon company. As a result, we develop an auto recognition system which makes it possible to get tag's information wirelessly. Also, it has a simple circuit structure and is small in size.

• Convergence Security Journal
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• v.15 no.2
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• pp.25-31
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• 2015

While information and communication develop, the Electronic commerce payment system is progressing. Recently, a government established the electronic commerce activation policy which simplified a payment Through this policy, the information which the financial company monopolizes can be fused with the other industry and create the popularization use of the electronic payment service and value added services. But on the other hand, the concern for the security is very high, Accordingly, the finnancial institute take a restriction of the requirements for the participation company according to the financial scale, this policy is led by the private institue, rather making a participation of fin tech venture difficulty. This paper tries to deal with the technical and legal problems for the activation of electronic payment system and fin tech. So I will examine the security matter that follows in grifting the innovation technology onto the existing payment service and propose a desirable way to improve the current legislation.

• Journal of Information Technology Application
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• v.3 no.1
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• pp.1-21
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• 2001

The explosive growth of the Internet and the increasing popularity of the World Wide Web have generated significant interest in the development of electronic commerce in a global online marketplace. The rapid adoption of the Internet as a commercial medium is rapidly expanding the necessity of Web advertisement as a new communication channel. if proper Web advertisement could be suggested to the right user, then effectiveness of Web advertisement will be raised and it will help company to earn more profit. So, this article describes a personalized advertisement technique as a part of intelligent customer services for an electronic newspaper provide. Based on customers history of navigation on the electronic newspapers pages, which are divided into several sections such as politics, economics, sports, culture, and so on, appropriate advertisements (especially, banner ads) are chosen and displayed with the aid of machine learning techniques, when customers visit to the site. To verify feasibility of the technique, an application will be made to one of the most popular e-newspaper publishing company in Korea.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1904-1917
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• 2016

The moving average filter (MAF) is widely utilized to improve the disturbance rejection capability of phase-locked loops (PLLs). This is of vital significance for the grid-integration and stable operation of power electronic converters to electric power systems. However, the open-loop bandwidth is drastically reduced after incorporating a MAF into the PLL structure, which makes the dynamic response sluggish. To overcome this shortcoming, some new techniques have recently been proposed to improve the transient response of MAF-based PLLs. In this paper, a comprehensive performance comparison of advanced MAF-based PLL algorithms is presented. This comparison includes HPLL, MPLC-PLL, QT1-PLL, and DMAF-PLL. Various disturbances, such as grid voltage sag, voltage flicker, harmonics distortion, phase-angle and frequency jumps, DC offsets and noise, are considered to experimentally test the dynamic performances of these PLL algorithms. Finally, an improved positive sequence extraction method for a HPLL under the frequency jumps scenario is presented to compensate for the steady-state error caused by non-frequency adaptive DSC, and a satisfactory performance has been achieved.

• KIEE International Transactions on Power Engineering
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• v.5A no.1
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• pp.85-92
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• 2005

In this paper, Nash equilibriums of generation markets are investigated using a game theory application for simplified competitive electricity markets. We analyze the characteristics of equilibrium states in N-company spot markets modeled by uniform pricing auctions and propose a new method for obtaining Nash equilibriums of the auction. We assume that spot markets are operated as uniform pricing auctions and that each generation company submits its bids into the auction in the form of a seal-bid. Depending on the bids of generation companies, market demands are allocated to each company accordingly. The uniform pricing auction in this analysis can be formulated as a non-cooperative and static game in which generation companies correspond to players of the game. The coefficient of the bidding function of company-n is the strategy of player-n (company-n) and the payoff of player-n is defined as its profit from the uniform price auction. The solution of this game can be obtained using the concept of the non-cooperative equilibrium originating from the Nash idea. Based on the so called residual demand curve, we can derive the best response function of each generation company in the uniform pricing auction with N companies, analytically. Finally, we present an efficient means to obtain all the possible equilibrium set pairs and to examine their feasibilities as Nash equilibriums. A simple numerical example with three generation companies is demonstrated to illustrate the basic idea of the proposed methodology. From this, we can see the applicability of the proposed method to the real-world problem, even though further future analysis is required.

• 전기의세계
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• v.20 no.1
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• pp.45-47
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• 1971

공업전자의 현황과 전망에서는 SCR을 주축으로 한 반도체소자를 이용한 Energy변환 및 제어의 분야의 반도체소자를 매개로한 Energy변환과 제어 및 기계의 전자화된 조절장치를 체계화한 전기공학의 분야에 대해 설명했으며, 우주통신과 우주선 추적에서는 아폴로 S대통일계통, Goddard식 거리속도추적계통, 중계위성에 대해 설명했으며 Feedback inbiological systmems lecture notes에서는 Familar definition of Feedback, Definition of Control Feedback에 대해 논하였다.

• Journal of Korea Technology Innovation Society
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• v.1 no.1
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• pp.96-105
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• 1998

Electronic cash affects central bank in many areas, in particular regarding the issuance of money, supervision of cashless payments, supervision of the banking system and monetary policy. The effects of electronic cash on central bank policies, the security and integrity of the payment system, and naturally also on single sector such as company engaged in the transport of money and valuables, depend mainly on the extent to which the new payment methods can replace cash. The possible development of electronic cash merits special attention from central banks for at least three reasons. First, central banks are concerned that the introduction of the new payment instrument should have no adverse effect on public confidence in the payment system and payment media. Second, although the substitution of electronic cash for other forms of money should not theoretically hamper central bank's ability to control the money supply, it might, however, have practial implications, at least in the long run, which need to be carefully examined. Third, because electronic cash may be used for payments of very small value, they have the potential, more than any other cashless instrument, to take over the role of notes and coins in the economy and, therefore, have implications for central bank's activities and revenues.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.6
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• pp.620-624
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• 2010

In this paper, design and manufactured UWB BPF. Manufactured UWB BPF can miniaturize the structure by controlling impedance and biographical one dimension that is allocated in transmission line each section. Proposed UWB BPF designed most suitable using Agilent company's ADS2008 Momentum and Ansoft company's HFSS 10. Manufactured UWB BPF has pass-band filter of 3.1 [GHz]~10.6 [GHz] and insertion loss is 0.39 [dB] in 8.3 [GHz], and reflection loss displayed special quality of 12.394 [dB] in 9.37 [GHz].

• Proceedings of the Korea Database Society Conference
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• 2010.06a
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• pp.249-264
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• 2010

Mobile banking is a subset of electronic banking which underlies not only the determinants of the banking business but also the special conditions of mobile commerce. Nowadays wireless networks are being evolved and diversified. In this situation The wireless e-commerce is in the limelight on new profits of Carriers. Because of this situation, the importance of mobile billing service is being emphasized. This paper searches the definition and service types of mobile banking, and suggests status and prospects of domestic mobile banking. We suggest the basic direction, the stage of development and functions of services by analyzing the cases of Nonghyup's. Finally we derive the critical factors from those and suggest the effect of introduction and the direction of development. From the customer perspective, mobile banking has many strengths. For example, it allows that all customers access banking service at anytime, anywhere more easily than telephone banking or pc banking. And it reduces the time and the effort for using the service. It enables the company to make a business against global customers. On the other hand, from the company perspective, it has a lot of potential that affect market share and reduce the costs of human and material resources which used to operate and support branches. However, it needs many efforts to reach at the stage of completion. And We will have to solve the problems that develop many contents, expend the range of services and raise the service convenience.