• KIEE International Transactions on Power Engineering
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• v.5A no.2
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• pp.144-151
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• 2005

This paper presents a framework for determining control strategies against unwanted tripping actions during relay operation that plays a very important role in cascading events leading to voltage collapse. The framework includes an algorithm for quick identification of possible zone 3 relay operation during voltage instability. Furthermore, it comes up with the control strategy of load shedding at the selected location with active power and relay margin criteria. In addition, Quasi Steady-State (QSS) simulation is employed to obtain time-related information that is valuable in the determination of control strategy. As a case study, an example applying the framework is shown with the modified New England 39-bus system.

• Proceedings of the Korea Society for Simulation Conference
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• 2003.06a
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• pp.115-119
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• 2003

It requires a great deal of efforts to maintain a distributed system. What is important here is that we should be able to upgrade/maintain a distributed system without stopping the system in operation. For this, what we need is a dynamic reconfigurable framework for highly available distributed systems. In this paper, we propose objects-hot-swapping methods as a solution to our problem. These methods permit us to dynamically upgrade/expand a system without stopping the system in operation. In addition, we analyze these methods and show that an approach based on proxy is the most efficient. Furthermore, we propose two proxy-based approaches: the first one based on the static proxy provides for a fast execution time but it is difficult to implement. The second one based on the dynamic proxy provides for a slow execution time but it is easier to implement. Finally, we propose a hot swapping framework for these static and dynamic proxy.

• Journal of information and communication convergence engineering
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• v.19 no.3
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• pp.175-179
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• 2021

Enhancing the reliability of the system is important for recent system-on-chip (SoC) designs. This importance has led to studies on fault diagnosis and tolerance. Fault-injection (FI) techniques are widely used to measure the fault-tolerance capabilities of resilient systems. FI techniques suffer from limitations in relation to environmental conditions and system features. Moreover, a hardware-based FI can cause permanent damage to the target system, because the actual circuit cannot be restored. Accordingly, we propose a simulation-based FI framework based on the Verilog Procedural Interface for measuring the failure rates of SoCs caused by soft errors. We execute five benchmark programs using an ARM Cortex M0 processor and inject soft errors using the proposed framework. The experiment has a 95% confidence level with a ±2.53% error, and confirms the reliability and feasibility of using proposed framework for fault analysis in SoCs.

• Electronics and Telecommunications Trends
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• v.38 no.4
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• pp.95-103
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• 2023

The importance of the decentralized training with decentralized execution (DTDE) framework is well-known in the study of multiagent reinforcement learning. In many real-world environments, agents cannot share information. Hence, they must be trained in a decentralized manner. However, the DTDE framework has been less studied than the centralized training with decentralized execution framework. One of the main reasons is that many problems arise when training agents in a decentralized manner. For example, DTDE algorithms are often computationally demanding or can encounter problems with non-stationarity. Another reason is the lack of simulation environments that can properly handle the DTDE framework. We discuss current research trends in the DTDE framework.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.4
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• pp.208-215
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• 2024

The Sortie Generation Rate (SGR), which measures the number of sorties that an airbase can produce per unit of time, is crucial for assessing operational capacity. However, the unique spatial and environmental constraints on aircraft carriers complicate the direct application of land-based SGR studies to maritime settings. This study introduces a framework for analyzing the Sortie Generation Process (SGP) on aircraft carriers, using discrete event simulation adapted to these constraints. This approach conceptualizes the SGP similar to a logistics and production system, wherein sorties are systematically generated through the operations of the aircraft. The proposed framework defines and implements the necessary simulation functions with the discrete event simulation method for the purpose of SGP analysis. Through a series of experiments, this study demonstrates the framework's effectiveness and its practical applicability to aircraft carrier operations, potentially enhancing sortie generation capabilities in naval aviation.

• Journal of Internet Computing and Services
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• v.25 no.4
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• pp.1-6
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• 2024

OMNeT++ (Objective Modular Network Testbed in C++) is an extensible and modular C++ simulation library and framework for building network simulators. OMNeT++ provides simulation models independently developed for various fields, including sensor networks, and Internet protocols. This enables researchers to use the tools and features required for their desired simulations. OMNeT++ uses NED (Network Description) Language to define nodes and network topologies, and it is able to implement the creation and behavior of defined network objects in C++. Moreover, the INET framework is an open-source model library for the OMNeT++ simulation environment, containing models for various networking protocols and components, making it convenient for designing and validating new network protocols. This paper aims to explain the concepts of OMNeT++ and the procedures for network simulation using the INET framework to assist novice researchers in modeling and analyzing various network scenarios.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.2
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• pp.15-22
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• 2014

This paper proposes a CUDA simulation framework for non-x86 computing platforms based on QEMU and GPGPU-sim. Previous simulators for heterogeneous computing platforms did not support for non-x86 CPU models or CUDA computing platform. In this work, we combined the QEMU and the GPGPU-Sim to support the non-x86 CPU models and the CUDA platform, respectively. This approach provides a simulation framework for CUDA computing on non-x86 CPU models.

• Steel and Composite Structures
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• v.44 no.5
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• pp.651-676
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• 2022

Most of the experimental, theoretical, and numerical studies on the stability of functionally graded composites are deterministic, while there are full of complex interactions of variables with an inherently probabilistic nature, this paper presents a non-intrusive framework to investigate the stochastic nonlinear buckling behaviors of porous functionally graded cylindrical shells exposed to inevitable source-uncertainties. Euler-Lagrange equations are theoretically derived based on the three variable refined shear deformation theory. Closed-form solutions for the shell buckling loads are achieved by solving the deterministic eigenvalue problems. The analytical results are verified with numerical results obtained from finite element analyses that are conducted in the commercial software ABAQUS. The non-intrusive framework is completed by integrating the Monte Carlo simulation with the verified closed-form solutions. The convergence studies are performed to determine the effective pseudorandom draws of the simulation. The accuracy and efficiency of the framework are verified with statistical results that are obtained from the first and second-order perturbation techniques. Eleven cases of individual and compound uncertainties are investigated. Sensitivity analyses are conducted to figure out the five cases that have profound perturbative effects on the shell buckling loads. Complete probability distributions of the first three critical buckling loads are completely presented for each profound uncertainty case. The effects of the shell thickness, volume fraction index, and stochasticity degree on the shell buckling load under compound uncertainties are studied. There is a high probability that the shell has non-unique buckling modes in stochastic environments, which should be known for reliable analysis and design of engineering structures.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.7
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• pp.685-692
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• 2009

This paper dealt with the development of the Framework for Multidisciplinary Design Optimization for the rotorcraft design concept and the building process of KHP(Korea Helicopter Project) - SDM(Simulation Data Management) system to manage various analysis data, which are used in the rotorcraft development phase. KHP-SDM RMDO(Rotorcraft Multidisciplinary Design Optimization) framework, which applied optimization modules of KHP-SDM and integrated the developed Multidisciplinary analysis modules, was constructed in the KHP-SDM. The results of the rotorcraft conceptual design using KHP-SDM RMDO showed that the framework was evaluated to be successfully constructed.

• The Korean Journal of Ecology
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• v.8 no.4
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• pp.179-196
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• 1985

By using temperatures as a key variable, a simulation model was constructed to predict the size and developmental speed for the German cockroach population. The following three research steps were conducted to implement the individual simulation technique to represent the basic life system of the cockroach. First, informations on developmental periods and survival rates in each life stage were obtained through rearing experiments at five different temperatures. Secondly, biological parameters needed for modeling were obtained based on these rearing results. The logistic equation was applied to calculating the developmental speed, while the averages of survival rates were utilized as parameters determining population size. And thirdly, a basic life model was constratued in a stimulative framework in FORTRAN for predicting the populating development on the individual basis. For this purpose the biological characteristics, such as life stage, age in days, developmental speed, fecundity, etc., were assigned as an inherent attribute of the transactiion so that they could accompany each individual automatically all through the simulation. This gave the model flexibility and applicability in representing the isnect life system. The save memory space in computer programing, two files were utilized in translocating the individual informations each other as time proceeded. The developed model could be effectively used as a strategic tool in interpreting and managing the cockroach population. It was also suggested in this study that the individual simulation could efficiently serve as a basis to formulate a fundamental framework on which the advanced and complex life process could be built.