• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.8
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• pp.3328-3349
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• 2020

With rapid development of ubiquitous computing and location-based services (LBSs), human trajectory data and associated activities are increasingly easily recorded. Inappropriately publishing trajectory data may leak users' privacy. Therefore, we study publishing trajectory data while preserving privacy, denoted privacy-preserving activity trajectories publishing (PPATP). We propose S-PPATP to solve this problem. S-PPATP comprises three steps: modeling, algorithm design and algorithm adjustment. During modeling, two user models describe users' behaviors: one based on a Markov chain and the other based on the hidden Markov model. We assume a potential adversary who intends to infer users' privacy, defined as a set of sensitive information. An adversary model is then proposed to define the adversary's background knowledge and inference method. Additionally, privacy requirements and a data quality metric are defined for assessment. During algorithm design, we propose two publishing algorithms corresponding to the user models and prove that both algorithms satisfy the privacy requirement. Then, we perform a comparative analysis on utility, efficiency and speedup techniques. Finally, we evaluate our algorithms through experiments on several datasets. The experiment results verify that our proposed algorithms preserve users' privay. We also test utility and discuss the privacy-utility tradeoff that real-world data publishers may face.

• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.88-96
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• 2001

Future mobile communication networks, which consist of ATM-based B-ISDN backbone networks and wireless ATM networks, will provide u user with broadband connection and QoS service. These network systems need the lossless handoff methods which support user mobility, satisfy ATM features such as ATM cell ordering and no ATM cell duplication and minimize buffer requirement for ATM cell buffering. In this paper we suggest a multicast-based handoff method to supp$\alpha$t lossless connection as well as to minimize buffer overhead. It establishes a dynamic multicast connection between source terminal and wireless member AP (access point)s. When the mobile terminal receives data packet correctly, it notifies the positive acknowledgement of the packet to all member APs. And member APs then release the MT related temporary buffer space for MT's future movement. Therefore member APs can eliminate unnecessary buffer usage and manage the buffer space efficiently. Analysis result shows that our handoff method has better performance in buffer requirement for lossless and seamless connection services over VCT (virtual connection tree) method and other dynamic multicast-based handoff methods.

• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.4
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• pp.131-142
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• 2010

Due to the development of the Internet, Internet banking that we are liberated from time and space has evolved into banking system. So modern life became comfortable. However, Dysfunction (malicious Information leakage and hacking etc.) of the Internet development has become a serious social problem. According to this, The need for security is rapidly growing. In this paper, we proposed the Internet Banking Authentication System using a dual-channel in OTP(One Time Password) authentication. This technology is that A user transfer transaction information to Bank through one Internet channel then bank transfer transaction information to user using the registered mobile phone or smart phone. If user confirm transaction information then bank request user's OTP value. User create OTP value and transfer to bank and bank authenticate them throgth the ARS. If authentication is pass then transaction permitted. Security assessment that the proposed system, the security requirement that the confidentiality and integrity, authentication, repudiation of all of the features provide a key length is longer than the current Internet banking systems, such as using encryption, the security provided by the Financial Supervisory Service Level 1 rating can be applied to more than confirmed.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.3
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• pp.1-10
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• 2004

Quite many papers about moving objects database (MOD) have been Published. Most of them are concerning of improving efficiency of updating policy, but none of them talks about verification of system's requirements. No matter how efficient updating policy is employed, a system designer still has to verify if the MOD satisfies user's requirement at the beginning of system lifestyle. For example, if a MOD serves n moving objects, then the designer must verity if it can update information for n moving objects and provide new information to moving objects within specified time limit. For the purpose of requirement analysis of MODs, we build a Petri net model for MOD using Design/CPN, and then we show how to verify whether the MOD satisfies user's requirements by simulation. The contribution of this paper is providing a simulation model for requirement analysis of MOD for the first time. The model is expansion of our previous fuzzy-timing Petri net model. The distance-based updating policy, and distributed database management system are reflected in this model and system analysis for moving objects is considered. It is built in Design/CPN so that the simulation can be automatically performed. The application of our model is not limited to requirement analysis, it is useful to study other MOD design issues, such as the trade-offs between update cost and information accuracy, and between the tim interval needed for updating database and MOD system resources, etc.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.197-198
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• 2008

In this paper, we study an opportunistic scheduling scheme for the OFDMA system with streaming services. The service is modeled by using the appropriate utility function. We formulate a stochastic optimization problem that aims at maximizing network utility while satisfying the QoS requirement of each user. The problem is solved by using the dual approach and the stochastic sub-gradient algorithm.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10a
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• pp.250-252
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• 2001

With the growth in computer and network technologies, some content-based music retrieval systems have been developed. However, their retrieval efficiency does not satisfy user's requirement yet. Of course users hope to have a more efficient and higher precision for music retrieval. In this paper so for these reasons, we Propose an efficient content-based music retrieval algorithm using melodies represented as music sequences. From the experimental result, it is shown that the proposed algorithm has higher exact rate than the related algorithms.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.961-963
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• 2013

NTIS는 세계 최초의 국가 R&D 정보 지식 포털으로 서비스 활용도와 인지도 제고를 위하여 웹진을 활용하고자 한다. 본 논문에서는 공공기관의 웹진 운영 현황과 웹진 운영에 대한 이용자 의견을 살펴보고 NTIS 웹진 제작 방안에 대하여 논의하고자 한다.

• The KIPS Transactions:PartD
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• v.9D no.4
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• pp.651-658
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• 2002

This paper suggests the scenario composition supporting method, which can be used to perform integration test based on specification, and implemented a scenario composition supporting tool. To compose scenario for object-oriented integration testing, requirement specification, Process definition table and program to table relation diagram are used. In addition, requirement trace table is created. It can check user's requirements, quickly and exactly, dividing former three fables into the stages of requirement analysis, design, and test. The output of scenario composition supporting tool plays a guide part in composing scenario. This tool can reduce scenario composition effort of quality for the checking team and prevent an omission of requirement and input of errors during the test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1860-1868
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• 2009

As general use of Mobile devices, the integration operations between the Home network is active. For popularization of Home network interface of normalizing in user's use convenience offer must, and developer must be able to cope sensitively in change development and requirement, hereafter such as maintenance with normalized interface environment. In the case of Home network, because several terminal information devices have to be used to a Home server, user establishment and exclusion should be easy and should adapt fast in requirement alteration and maintenance. In this paper, we designed and implemented mobile home network components with applied efficient information transmission interface that can be applied to the various application of OSGi platform. These components can respond quickly of user requirements and maintenance and that can be reuse and evolved.

• Journal of KIISE:Software and Applications
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• v.36 no.2
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• pp.144-152
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• 2009

To provide intelligent service in mobile environment, it needs to estimate user's intention or requirement, through analyzing context information of end-users such as preference or behavior patterns. In this paper, we infer context information from uncertain log stored in mobile device. And we propose the inference method of end-user's behavior to match context information with service, and the proposed method is based on context-tree. We adopt bayesian probabilistic method to infer uncertain context information effectively, and the context-tree is constructed to utilize non-numerical context which is hard to handled with mathematical method. And we verify utility of proposed method by appling the method to intelligent phone book service.