• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.1033-1039
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• 2005

Parallel and distributed simulation is concerned with the efficient execution of large-scale discrete event simulation models on multiprocessors and distributed platforms. After the development of WWW, many efforts in the parallel and distributed simulation have been made for modeling, particularly building simulation languages and creating model libraries that can be assembled and executed over WWW. However, web-based parallel and distributed simulation is restricted by heterogeneous computing environments. Recently, the advent of XML and web services technology has made these efforts enter upon a new phase. Especially, the web services as a distributed information technology have demonstrated powerful capabilities for scalable interoperation of heterogeneous systems. This paper aims to develop and evaluate the parallel and distributed simulation using the web services technology. In particular, a prototype multi-pass simulation framework is implemented using Java-based web services technology. It focuses on the efficiency of multi-pass simulation used for optimization through the distribution of simulation replication to several simulation service providers. The development of parallel and distributed simulation using web services will help solve efficiently large-scale problems and also guarantee interoperability among heterogeneous networked systems.

• Journal of Software Assessment and Valuation
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• v.16 no.2
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• pp.77-85
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• 2020

In this paper, We studied the operation of distributed ledger technology used as a core technology for smart contracts and the components of distributed ledger technology. As a solution applying the entity of distributed ledger technology to NoE, we proposed the protocol of the distributed ledger technology using the thing user social group management function of NoE protocols being standardized in ISO/IEC JTC1 SC6. The management function of things user social group in NoE provides stable protocol functions and data transmission management, and provides group management functions such as member discovery function and data transmission channel management function. It is expected to be useful for member management functions of distributed ledger nodes by providing a service that apply the component of distributed ledger technology. We intend to actively reflect this technology in the future network functions of ISO/IEC JTC1 SC6, which is undergoing standardization.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.4
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• pp.919-943
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• 2019

Distributed ledger technology, which is attracting attention as an emerging technology related to the 4th Industrial Revolution, is implemented as an open source based distributed ledger technology system and widely used for development with various applications (or services), but the security functions provided by the distributed general ledger system are very insufficient. This paper proposes security enhancements for distributed ledger technology systems based on open source. To do so, potential security threats that may occur under running an open source based distributed ledger technology systems are identified and security functional requirements against the security threats identified are provided by analyzing legislation and security certification criteria (ISMS-P). In addition, it proposes a method to implement the security functions required for an open source based distributed ledger technology systems through analysis of security functional components of Common Criteria (CC), an international standard.

• Electronics and Telecommunications Trends
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• v.35 no.2
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• pp.50-68
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• 2020

Distributed Ledger Technology (DLT) refers to a process and related technologies that enable a person to safely suggest, verify, and record state changes (usually updates) to synchronize ledgers distributed across network nodes. DLTs are becoming increasingly important as data management requirements evolve. Therefore, they need to understand the current state of standards (such as distributed storage and access technologies) to address future requirements. This paper provides ITU-T FG-DLT standard activities, such as standardization ization trends, use cases, reference architectures, platform evaluation criteria and future prospects.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.95_96
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• 2009

In this paper, a new algorithm of Integrated Volt/Var Control (IVVC) is proposed using Volt/Var control for the Distribution Automation System (DAS) based on the modeling of the distributed load and the distributed current. In the proposed, the load flow based on the modeling of the distributed load with Distributed Generation and the distributed current are estimated from constants of four terminals using the measurement of the current and power factor from a Feeder Remote Terminal Unit (FRTU). For Integrated Volt/Var Control (IVVC), the gradient method is applied to find optimal solution for tap and capacity control of OLTC (On-Load Tap Changers), SVR (Step Voltage Regulator), and SC (Shunt Condenser). What is more Volt/Var control method is proposed using moving the tie switch as well as IVVC algorithm using power utility control. In the case studies, the estimation and simulation network have been testified in Matlab Simulink.

• International Journal of Computer Science & Network Security
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• v.23 no.5
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• pp.207-211
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• 2023

Traditional methods for datamining typically assume that the data is small, centralized, memory resident and static. But this assumption is no longer acceptable, because datasets are growing very fast hence becoming huge from time to time. There is fast growing need to manage data with efficient mining algorithms. In such a scenario it is inevitable to carry out data mining in a distributed environment and Frequent Itemset Mining (FIM) is no exception. Thus, the need of an efficient incremental mining algorithm arises. We propose the Distributed Incremental Approximate Frequent Itemset Mining (DIAFIM) which is an incremental FIM algorithm and works on the distributed parallel MapReduce environment. The key contribution of this research is devising an incremental mining algorithm that works on the distributed parallel MapReduce environment.

• Journal of the Korean Professional Engineers Association
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• v.30 no.2
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• pp.79-86
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• 1997

As network has high speed and wide communication capability, users demand diverse and new software to satisfy their needs. To meet users needs, the softwares for multimedia or groupware or distributed virtual environments can communicate the widely distributed information fast and accurately. Even though the technology for this is under development, it is deficient to support the reliable computer communication. Distributed Object System aims, as the new paradigm of distributed system software development to overcome this problem, to obtain in distributed environment the easiness of development and management, expandability, reusability which object oriented technologies support by solving the complexity of communication processing through the object oriented methods. This paper aims to introduce distributed object system, its technological properties and the current status and trend of technology development related to its standardization. Additionally, with explaining the Replicated Shared Object System(RSOS) which is developed in our country as one of the distributed object systems, its future prospects and technical issues are discussed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.6
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• pp.2606-2626
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• 2016

This article investigates the distributed data storage problem in the space information network (SIN) using distributed fountain codes. Since space nodes in the SIN are resource-limited, in order to reduce energy consumption while improving the storage reliability, an efficient distributed storage based on fountain codes and probabilistic broadcasting (DSFPB) strategy is proposed. In the proposed strategy, source packets are disseminated among the entire network according to probabilistic broadcasting (PBcast), and the final degree distribution is close to the desired robust soliton distribution (RSD), this is benefited from the appropriate packets encoding procedure of the proposed strategy. As presented by the analysis and simulations, the total cost of data dissemination is greatly reduced compared with existing representative strategies, while improving the decoding performance.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.84-87
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• 2000

In this paper, a high gain-broad bandwidth MMIC distributed amplifier was designed using cascaded single section distributed amplifier configuration. The PHEMT for this studies was fabricated at our lab The PHEMT has a 0.2 $\mu\textrm{m}$ gate length. a 80 $\mu\textrm{m}$ unit gate width and 4 gate fingers. A designed MMIC amplifier have higher S$\sub$21/ gain than the common distributed amplifier using the same number of active devices. From the simulated result, we obtained that the S$\sub$21/ gain of DC ∼ 20 GHz bandwidth was 15.6 dB and flatness was ${\pm}$0.9 dB, and input and output reflection coefficient were lower than -8 dB. The simulated gain shows an improvement 7.3 dB compared with those of conventional distributed amplifier. And the chip size is 2.0 ${\times}$ 1.2 $\textrm{mm}^2$.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.9
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• pp.2134-2153
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• 2013

A network-coding-based scheme is proposed to improve the energy efficiency of distributed storage systems in WSNs (Wireless Sensor Networks). We mainly focus on two problems: firstly, consideration is given to effective distributed storage technology; secondly, we address how to effectively repair the data in failed storage nodes. For the first problem, we propose a method to obtain a sparse generator matrix to construct network codes, and this sparse generator matrix is proven to be the sparsest. Benefiting from this matrix, the energy consumption required to implement distributed storage is reduced. For the second problem, we designed a network-coding-based iterative repair method, which adequately utilizes the idea of re-encoding at intermediate nodes from network coding theory. Benefiting from the re-encoding, the energy consumption required by data repair is significantly reduced. Moreover, we provide an explicit lower bound of field size required by this scheme, which implies that it can work over a small field and the required computation overhead is very low. The simulation result verifies that the proposed scheme not only reduces the total energy consumption required to implement distributed storage system in WSNs, but also balances energy consumption of the networks.