• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.2
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• pp.371-378
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• 2002

In the resent years, the term mobile agent is probably one of the most overused words in many appliable areas of distributed open systems as electronic commerce and electronic data interchange, and it has very different meanings in the area of artificial intelligence, network management, or distributed systems. However, the use of mobile agent adds significant problems, primarily in the area of EC/EDI. Therefore it is very important to control the roaming agents to keep one's privacy or property in distributed open networks. The surge in secure intranets for commercial applications provides a robust, secure environment to which trading partners can increasingly entrust their interactions to some mobile agents. In this paper, we introduce a mechanism to protect mobile agent itself from the malicious server he is visiting and also we introduce a mechanism to protect vital resources of the open systems as internet.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.1
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• pp.14-20
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• 2012

CoMP(Coordinated Multi-Point transmission and reception) refers to a cooperative transmission strategy to control the interference from adjacent base stations in cellular mobile communication systems, which efficiently enhances the data throughput of the systems. As the number of the base stations participating in cooperative transmission increases, however, a larger amount of information exchange to carry the CSI(Channel State Information) of the mobile terminals is required. In this paper, we propose a partial CoMP transmission method for systems under the constraint of finite feedback information data. This method selects candidates of base stations which can provide high efficiency gain when they participate in the CoMP set. To achieve this, the cooperative base station combination is constructed by considering the preferred base stations of users. The cooperative base station combinations are dynamically applied since the preferred base station combinations of users may be different. We perform computer simulations to compare performance of the non-CoMP, full-CoMP and partial CoMP in terms of the average throughput using finite feedback and demonstrate the performance improvement of the proposed method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.701-704
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• 2007

Recently, More and more consumer enjoy the finance service such as settling, account transferring, stocks investment, and so via mobile device. In the mobile environment, data transferring between the devices is formatted as XML. However, the common XML file is exposed to the attack such as hacking and malignity code, to satisfy security of mobile environment is very difficult. The problem is more seriously at the open platform such as WIPI that is developed by our country. So there is enough reason to propose one system to protect the import data. In this paper, we development the system to digital signature and signature the XML document in order to protect data, and the system is observing the recommendation of the XML Signature Syntax and Processing by W3C. When designing and composition the system, we use the digital signature algorithm RSA, DSA, KCDSA, and HMAC, etc. we test the system at the open WIPI platform.

• The KIPS Transactions:PartD
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• v.12D no.1 s.97
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• pp.1-12
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• 2005

The XML is emerging as standard language for data exchange on the Web. Therefore a demand of XML Schema(W3C MLL Schema Spec.) that verifies XML document becomes increasing. However, XML Schema has a weak point for design because of its complication despiteof various data and abundant expressiveness. This paper shows a simple way of design for XML Schema using a fundamental means for database design, the Entity-Relationship model. The conversion from the Entity-Relationship model to XML Schema can not be directly on account of discordance between the two models. So we present some algorithms to generate XML Schema from the Entity-Relationship model. The algorithms produce XML Schema codes using a hierarchical view representation. An important objective of this automatic generation is to preserve XML Schema's characteristics such as reusability, global and local ability, ability of expansion and various type changes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.10
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• pp.938-946
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• 2012

Interference alignment (IA) is a data transmission technique that achieves the maximum degrees-of-freedom (DoF) in the multiuser interference channel for high signal-to-noise ratios (SNRs). However, most prior works on IA are based on the unrealistic assumption that perfect and global channel-state information (CSI) is available at all transmitters and receivers. In this paper, we propose the efficient design of feedback framework for IA that substantially suppresses the feedback overhead. While the feedback overhead in the conventional IA quadratically increases with K, the proposed feedback scheme supports the sequential exchange of computed IA precoders between transmitters and receivers and reduces the feedback overhead that linearly scales with K. Moreover, we analyze the residual interference due to the quantization error in limited feedback and propose the ordered IA algorithm that selects IA pair to minimize the sum residual interference in given channel realizations.

• Journal of the Korea Society of Computer and Information
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• v.25 no.8
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• pp.9-21
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• 2020

With the proliferation of RDF knowledge graphs(KGs), there arose a need of a standardized schema representation of the graph model for effective data interchangeability and interoperability. The need resulted in the development of SHACL specification to describe and validate RDF graph's structure by W3C. Relational databases(RDBs) are one of major sources for acquiring structured knowledge. The standard for automatic generation of RDF KGs from RDBs is R2RML, which is also developed by W3C. Since R2RML is designed to generate only RDF data graphs from RDBs, additional manual tasks are required to create the schemas for the graphs. In this paper we propose an approach to automatically generate SHACL schemas for RDF KGs populated by R2RML mappings. The key of our approach is that the SHACL shemas are built only from R2RML documents. We describe an implementation of our appraoch. Then, we show the validity of our approach with R2RML test cases designed by W3C.

• Journal of the Korea Society of Computer and Information
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• v.15 no.12
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• pp.85-92
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• 2010

There is an authentication method for participants with an encrypted ID and password as a symmetric-key in multilateral video conferencing. It is hard to manage when the security-keys makes many while the transportation processing for the encryption and decryption get complicated when the video conferencing involves a number of participants and the third party as an attackers to gain unauthorized symmetric-key to access video conference which makes a problem less secrecy. This study suggests three ways to enhance security in video conference: first, we present PKI-based X.509 certificate for authenticating the participants of multilateral conferencing and we suggest to encode and decode the video conference media data using a secrecy key created by each of the conference participants; second, a more secured multilateral video conferencing can be expected in a group communication by using the participants secrecy key in creating and distributing group keys, where the group key will be renewed whenever there is change in the group member; and finally, we suggest to encode the RTP payload of the media data before transmission.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6B
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• pp.683-688
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• 2011

Current is change to concept that management traffic of ship os magnified gradually to near shore waters from harbor. Therefore, introducing the technology of AIS in the ground station, lighthouse, bouy, sea facilities etc.. that is support equipment for safety sailing of ship and safety security of harbor and ship administration. The operation and maintenance of AIS for aids to navigation are required to efficient method. With this actuality, sea advanced nation of EU, USA, Japan that has been apply for developing AtoN AIS equipment that is connected equipment of technology standard in IALA. Because of it is expected to depend equipment in income, that is required to domestic technology of the AtoN AIS. This paper is targeted to development that is suitable automation AtoN AIS equipment in environmental peculiarity for constructor AtoN operating administration center. It has been realization send protocol for information interchange.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.3
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• pp.577-584
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• 2017

Long Term Evolution device-to-device (LTE D2D) is a key technology to mitigate data traffic load in a cellular system. It facilitates direct data exchange between neighboring users, which is preceded by D2D discovery. Each device advertises its presence to neighboring devices by broadcasting its discovery message. In this paper, we develop a mathematical analysis to assess the probability that discovery messages are successfully transmitted at the D2D discovery stage. We make use of stochastic geometry for modeling spatial statistics of nodes in a two dimensional space. It reflects signal to noise plus interference ratio (SINR) degradation due to resource collision and in-band emission, which leads to the discovery message reception probability being modeled as a function of the distance between the transmitter and the receiver. Numerical results verify that the newly developed analysis accurately estimates discovery message reception probabilities of nodes at the D2D discovery stage.

• Journal of KIISE:Databases
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• v.36 no.2
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• pp.150-167
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• 2009

XML has become the new standard for storing, exchanging, and publishing of data over both the internet and the ubiquitous data stream environment. As demand for efficiency in handling XML document grows, labeling scheme has become an important topic in data storage. Recently proposed labeling schemes reflect the dynamic XML environment, which itself provides motivation for the discovery of an efficient labeling scheme. However, previous proposed labeling schemes have several problems: 1) An insertion of a new node into the XML document triggers re-labeling of pre-existing nodes. 2) They need larger memory space to store total label. etc. In this paper, we introduce a new labeling scheme called a Circle Labeling Scheme. In CLS, XML documents are represented in a circular form, and efficient storage of labels is supported by the use of concepts Rotation Number and Parent Circle/Child Circle. The concept of Radius is applied to support inclusion of new nodes at arbitrary positions in the tree. This eliminates the need for re-labeling existing nodes and the need to increase label length, and mitigates conflict with existing labels. A detailed experimental study demonstrates efficiency of CLS.