• The Transactions of the Korea Information Processing Society
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• v.3 no.7
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• pp.1697-1706
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• 1996

This paper presents the design and the implementation of a MissCW(Multi user Interactive System for Synchronous Collaborative Writing). The document model DMDA(Distributed Multimedia Document Architecture) of MissCW consists of the logical structure, presentation style object, and mark object. The windows. The collaborative editor of this system proposes a structure oriented editing mechanism to combine distrbuted objects into one document. The middleware SOM(Shared Object Manager) maintains shared objects consistently and helps application programs use objects efficiently. The infrastructure of this system is a hybrid structure of replicated and centralized architectures, that is to maintain shared objects consistently inside of SOM and to reduce the overhead of network traffic. The central part is a virtual node which corresponds to the Object Controller of SOMwith the SOT(Shared Objet Table).

• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.573-581
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• 2004

Recently, the rapid growth of Internet technology and the deployment of high speed networks make many kinds of multimedia services possible. Preexisting multimedia services are designed based on the client/server model which has the problems such as the network failure and the low speed communication due to the high load on the central server. In order to solve these problems, peer-to-peer networks are introduced and expanded through Internet environments. In this paper, we propose a pure peer-to-peer network based resource discovery mechanism for multimedia services. In the proposed scheme, each host maintains the location information of resources which are recently requested by other hosts as well as that oi the replicas of local resources. The proposed scheme has the faster response time and incurs the smaller traffic than the preexisting discovery schemes in pure peer-to-peer network environments. Also, by decentralizing the location information and differentiating the reply path, our proposed scheme can solve the search result loss problem that occurs when the network is unsettled.

• The KIPS Transactions:PartD
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• v.12D no.2 s.98
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• pp.289-302
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• 2005

The mobile agent has very various performance according to the element of communication number of times between hosts, quantity of transmission data agent's size, network state etc. specially, migration method is caused much effect in whole performance of distributed system. Most existing migration methods have simplicity structure that it moves doing to accumulate continuously result after achieving task by visiting host in the fixed order. Therefore, in case there are situation such as fault, obstacle, and service absence etc. This can be inefficient due to mobile agent increased network required time. In this paper, we design and implementation Multicast Migration Model for minimizing network required time by solving this problems. Multicast Migration Model includes components such as mobile agent including call module and naming agent, which provides object replication information and distributed server's location transparence. And we evaluate and compare with existing migration method applying prototype system to verify implemented migration model.

• Convergence Security Journal
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• v.19 no.5
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• pp.107-118
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• 2019

Based on the Internet of Things technology, one of the core technologies of the fourth industrial revolution, our Ministry of Defense is also pushing to establish M-IoT in defense area to improve management efficiency, innovate military culture and strengthen military power. However, devices connected to the Military Internet of Things can be easily exposed to various of cyber threats as most of them are developed and with a focus on improving sensing and communication skills that collect and transmit data. And it is not easy to uniquely identify the numerous heterogeneous devices, and to establish a secure communication channel between devices or between devices and management servers. In this paper, based on PUF technology, we propose a novel key management scheme that can uniquely identify the various devices, and generate the secret keys needed for the establishment of a secure communication channel using non-replicable information generated by the PUF. We also analyze the efficiency of our proposed scheme through comparison with existing key management scheme and verify the logic and security using BAN Logic.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.1
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• pp.101-121
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• 2020

Technology and culture are converging with various industries to create added value of contents. In addition, the country is creating a foundation environment for grafting new technologies onto the cultural content. However, copyright infringement by voice demand and supply is continuously occurring for cultural contents with copyright, and more and more recently, there have been increasing cases of creating and operating sites with servers overseas to bypass monitoring on infringement sites. To prevent this, various copyright protection studies are under way in many areas, but the current detection and prevention technologies are largely reactive and therefore have problems of effectiveness. Accordingly, this paper proposes a model of the lifecycle of copyright infringement site to lay the foundation for preemptive response to the distribution of illegal copies through analysis of the lifecycle of copyright infringement site.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.4
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• pp.247-258
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• 2009

Distributed file systems running on a cluster of inexpensive commodity hardware are being recognized as an effective solution to support the explosive growth of storage demand in large-scale Internet service companies. This paper presents the design and implementation of BeanFS, a distributed file system for large-scale e-mail services. BeanFS is adapted to e-mail services as follows. First, the volume-based replication scheme alleviates the metadata management overhead of the central metadata server in dealing with a very large number of small files. Second, BeanFS employs a light-weighted consistency maintenance protocol tailored to simple access patterns of e-mail message. Third, transient and permanent failures are treated separately and recovering from transient failures is done quickly and has less overhead.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.3
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• pp.391-398
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• 2018

There are many problems caused by data sharing between general heterogeneous digital devices due to various interfaces. To solve this problem, this paper proposes heterogeneous data sharing with cloud service and mobile through D2D communication that supports communication between different devices. The proposed technique is used to reduce the load on the server to perform data synchronization. Also, in order to minimize data latency caused by data replication between different devices, a technique to enhance the speed of data writing with copying only the modified parts in the chunk list is adopted and cloud service model integrated with mobile environment is realized in order to minimize the network bandwidth consumed for synchronization for data sharing. Therefore, it is possible to share data in different spaces efficiently with maintaining data integrity and minimizing latency in data.

• Journal of Software Assessment and Valuation
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• v.16 no.1
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• pp.13-19
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• 2020

It can be seen that the infringement of copyright cases is increasing as the society becomes more complex and advanced. During the software copyright dispute, there may be a dispute over whether the software is duplicated and made into upgraded software. In this paper, we intend to propose an analysis method for determining whether to upgrade software. For the software upgrade analysis, a software similarity analysis technique was used. The analysis program covers servers, management programs, and Raspberry PC programs. The first analysis confirms the correspondence between program creation information and content. In addition, it analyzes the similarity of functions and screen composition between the submitted program and the program installed in the field. The second comparative analysis compares and analyzes similarities by operating two programs in the same environment. As a result of comparative analysis, it was confirmed that the operation and configuration screens of the two programs were identical. Thus, minor differences were found in a few files, but it was confirmed that the two programs were mostly made using the same or almost similar source code. Therefore, this program can be judged as an upgrade program.

• Journal of Korea Society of Industrial Information Systems
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• v.28 no.5
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• pp.41-54
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• 2023

Smart grid that supports efficient energy production and management is used in various fields and industries. However, because of the environment in which services are provided through open networks, it is essential to resolve trust issues regarding security vulnerabilities and privacy preservation. In particular, the identification information of smart meter is managed by a centralized server, which makes it vulnerable to security attacks such as device stolen, data forgery, alteration, and deletion. To solve these problems, this paper proposes a blockchain based authentication protocol for a smart meter. The proposed scheme issues an unique decentralized identifiers (DIDs) for individual smart meter through blockchain and utilizes a random values based on physical unclonable function (PUF) to strengthen the integrity and reliability of data. In addition, we analyze the security of the proposed scheme using informal security analysis and AVISPA simulation, and show the efficiency of the proposed scheme by comparing with related work.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.6
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• pp.367-378
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• 2006

A mobile phone has became as a payment tool in e-commerce and on-line banking areas. This trend of a payment system using various types of mobile devices is rapidly growing, especially in the Internet transaction and small-money payment. Hence, there will be a need to define its standard for secure and safe payment technology. In this thesis, we consider the service types of the current mobile payments and the authentication method, investigate the disadvantages, problems and their solutions for smart and secure payment. Also, we propose a novel authentication method which is easily adopted without modification and addition of the existed mobile hardware platform. Also, we present a simple implementation as a demonstration version. Based on virtual machine (VM) approach, the proposed model is to use a pseudo-random number which is confirmed by the VM in a user's mobile phone and then is sent to the authentication site. This is more secure and safe rather than use of a random number received by the previous SMS. For this payment operation, a user should register the serial number at the first step after downloading the VM software, by which can prevent the illegal payment use by a mobile copy-phone. Compared with the previous SMS approach, the proposed method can reduce the amount of packet size to 30% as well as the time. Therefore, the VM-based method is superior to the previous approaches in the viewpoint of security, packet size and transaction time.