• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.137-142
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• 2003

A fundamental study for developing a system of fault diagnosis of a pump is performed by using neural network. The acoustic signals were obtained and converted to frequency domain for normal products and artificially deformed products. The signals were obtained in various driving frequencies in order to obtain many types of data from a limited number of pumps. The acoustic data in frequency domain were managed to multiples of real driving frequency with the aim of easy comparison. The neural network model used in this study was 3-layer type composed of input, hidden, and output layer. The normalized amplitudes at the multiples of real driving frequency were chosen as units of input layer, Various sets of teach signals made from original data by eliminating some random cases were used in the training. The average errors were approximately proportional to the number of untaught data. The results showed neural network trained by acoustic signals can be used as a simple method far a detection of machine malfunction or fault diagnosis.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.5
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• pp.81-86
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• 2004

A fundamental study for developing a system of fault diagnosis of a pump is performed by using neural network. The acoustic signals were obtained and converted to frequency domain for normal products and artificially deformed products. The signals were obtained in various driving frequencies in order to obtain many types of data from a limited number of pumps. The acoustic data in frequency domain were managed to multiples of real driving frequency with the aim of easy comparison. The neural network model used in this study was 3-layer type composed of input, hidden, and output layer. The normalized amplitudes at the multiples of real driving frequency were chosen as units of input layer. Various sets of teach signals made from original data by eliminating some random cases were used in the training. The average errors were approximately proportional to the number of untaught data. The results showed neural network trained by acoustic signals can be used as a simple method for a detection of machine malfuction or fault diagnosis.

• Journal of the Korea Society for Simulation
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• v.8 no.4
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• pp.125-136
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• 1999

In the forthcoming public ATM/B-ISDN, the efficient resource management with pre-planned transit networking which public domain NNI signaling is essential to maintain high network utilization and to assure QoS to the multimedia service users. For this purpose the transit networks must be managed according to the bearer service capability which is defined by ATM Forum and ITU-T. In this paper, we introduce an implementation of ATM transit networking with ATM VP-XC(Virtual Path cross-connect) and US(Network Management System). The functions of ATM VP-XC and NMS have been simulated with OPNET 6.1 modules. We implemented the F4 OAM functions of ATM VP connection according to the ITU-T 1.610 recommendation. Also, the ATM VP transit networking is managed by the NMS according to the connection management architecture of the TWN(Telecommunications Management Network) /TINA ( Telecommunications Information Networking Architecture).

• International Journal of Contents
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• v.5 no.3
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• pp.14-18
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• 2009

Traditional methods and materials used for Korean buildings need to be well organized and managed so that they can be utilized in modernization of old buildings. Supporting web-based management of information of Korean traditional building materials helps spread the related knowledge. This paper identifies the characteristics of traditional building materials data, and develops an information structure to represent the related information effectively. It also describes design decisions on web-based user interfaces to support flexible browsing and retrieval of the managed data. As the traditional building data are described by old domain-specific technical terms, utility of the developed service might be limited to those who are familiar with the terms. As an approach to tackle this problem, the proposed system supports user tagging by allowing users to classify the stored information using their own terms, and also to retrieve data using the user-supplied tags.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.3
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• pp.916-937
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• 2023

Most of the existing Distributed Denial-of-Service mitigation schemes in Software-Defined Networking are only implemented in the network domain managed by a single controller. In fact, the zombies for attackers to launch large-scale DDoS attacks are actually not in the same network domain. Therefore, abnormal traffic of DDoS attack will affect multiple paths and network domains. A single defense method is difficult to deal with large-scale DDoS attacks. The cooperative defense of multiple domains becomes an important means to effectively solve cross-domain DDoS attacks. We propose an efficient multi-domain DDoS cooperative defense mechanism by integrating blockchain and SDN architecture. It includes attack traceability, inter-domain information sharing and attack mitigation. In order to reduce the length of the marking path and shorten the traceability time, we propose an AS-level packet traceability method called ASPM. We propose an information sharing method across multiple domains based on blockchain and smart contract. It effectively solves the impact of DDoS illegal traffic on multiple domains. According to the traceability results, we designed a DDoS attack mitigation method by replacing the ACL list with the IP address black/gray list. The experimental results show that our ASPM traceability method requires less data packets, high traceability precision and low overhead. And blockchain-based inter-domain sharing scheme has low cost, high scalability and high security. Attack mitigation measures can prevent illegal data flow in a timely and efficient manner.

• Convergence Security Journal
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• v.22 no.4
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• pp.169-178
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• 2022

In general, organizations operating multi-domain networks find it difficult to represent and manage multiple domain net works on a single screen space. Instead, most of them are managed with multiple screens visualizing network topology by domain or partitioning one screen area into multiple domains. We propose an efficient method to visualize the topology using only minimal connection information between domain-agnostic nodes in this work. This method visualizes the topology by utilizing centrality indices representing the influence of nodes in the network. Furthermore, the method dynamically segments the entire node's display area using virtual Root nodes to auto-separate domains and weights of child nodes and placing nodes in 3D space. Thus, although it is a straightforward method, the multi-domain network topology can be visualized with only minimal connection information between nodes.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.23-26
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• 1998

IP multicasting efficiently delivers a single datagram to multiple hosts. Its benefits have been demonstrated over the past six years on MBONE. Now, as the number of subnets in the MBONE are increased, the MBONE can no longer be managed as a single, flat routing domain. Its routing scalability must be improved. In this paper, to solve problem of routing scalability, serveral new multicast models for the internet are explained.

• Proceedings of the Technology Innovation Conference
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• 1998.06a
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• pp.57-90
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• 1998

This study attempts to explore the evolution paths of Korean SMEs'strategies and their technological teaming processes. Several different evolution paths are identified based on a dynamic strategic group analysis of 115 SMEs'strategy in the Korean electronic component industry for the period of 1990-1995. Further, inadept case analyses on technological learning processes in 5 firms are undertaken. Major findings of this study can be summarized as follows : 1) There are three dominant evolution paths in SMEs'strategy. First path indicates the evolution from a subcontractor or petty imitator group(a strategic group with the narrow product/market domain and the low level of accumulated resource/capabilities) into an innovator group(a strategic group with the narrow domain but high level of technological capability) by accumulating technological capabilities. Second, some firms move from a subcontractor group into a generalizer group(a strategic group with broad product/market domain but relatively low level of technological capability) by simply adding product lines. Third path involves firms which evolve from a subcontractor group into a production focus group(a strategic group with high level of production capability) by investing in production capabilities. 2) An in-depth case analysis shows those who succeeded in technological learning are managed by CEOs, who have technological expertise and strategic vision, and have made an effort to establish management practices to support innovation, such employee educational program, performance-based reward system, etc. The successful firms also aggressively pursue diverse external linkages with outside technology sources to learn product and process technologies. Fiendly, this study discusses several implications of the findings for the theoretical development and strategic management of small firms in Korea.

• Proceedings of the Korea Society for Simulation Conference
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• 2002.05a
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• pp.61-65
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• 2002

These days, in order to satisfy the complex and various demands of the customers, the telecommunication networks must provide rapid and flexible services, with the support of efficient service and network management systems. To satisfy these requirements, many objects for management have been released to manage network services and elements. But there are no efficient ways to manage these newly managed objects in object-oriented software. Therefore, we study several problems, when a subsystem using object-oriented technique is implemented. The first problem is that interface works between realized application programs using its technique. The second problem is that reusability of internal managed objects is difficult. In this paper, we will point out some problems and to solve these problems, we have proposed the Object Management System (OMS) architecture, which supports a transparent interface between object-oriented applications and the distributed data repositories. Also in order to manage efficient business objects stored in the different repositories, we suggest a method for integrating dynamic information resources in heterogeneous and distributed network environments. Finally, we applied OMS to TINA(Telecommunication Information Network Architecture) domain, implemented OMS, and verified it with SMV(Symbolic Model Verifier) which is model checking technology.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.269-273
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• 2008

In ubiquitous environments, clients move between domains freely and its activities in the other domains are growth. Like this environment, the service provider makes access or activity records what they are provided to clients. This record can make a privacy problem to recognize a person or trace some works. So this record must be kept and managed by user instead of the service provider. In this paper, we propose a system that can gather those records from the service provider to home domain server which client's managing by themselves. In addition, if remote domain manager requests that record by the legal process, system can transfer only a range of information which allowed by client to keep personal privacy.