• 전기학회논문지P
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• 제62권3호
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• pp.117-126
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• 2013

This paper is written for the development and application of boiler furnace pressure control algorithm and distributed control system of coal-fired power plant by the steps of design, coding, simulation test, site installation and site commissioning test. The control algorithms were designed in the shape of cascade control for two parts of furnace pressure control and induced draft fan pitch blade by standard function blocks. This control algorithms were coded to the control programs of distributed control systems. The simulator for coal-fired power plant was used in the test step and automatic control, sequence control and emergency stop tests were performed successfully like the tests of the actual power plant. The reliability was obtained enough to be installed at the actual power plant and all of distributed control systems had been installed at power plant and all signals were connected mutually. Tests for reliability and safety of plant operation were completed successfully and power plant is being operated commercially. It is expected that the project result will contribute to the safe operation of domestic new and retrofit power plants, the self-reliance of coal-fired power plant control technique and overseas business for power plant.

• 전기학회논문지
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• 제62권3호
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• pp.322-331
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• 2013

This paper describes the development of the pilot plant of distributed intelligent management system for a microgrid. For optimal control and management of microgrids, intelligent agents area applied to the microgrid management system. Each agent includes intelligent algorithms to make decisions on behalf of the corresponding microgrid entity such as distributed generators, local loads, and so on. To this end, each agent has its own resources to evaluate the system conditions by collecting local information and also communicating with other agents. This paper presents key features of the data communication and management of the developed pilot plant such as the construction of mesh network using local wireless communication techniques, the autonomous agent coordination schemes using plug-and-play functions of agents and contract net protocol (CNP) for decision-making. The performance of the pilot plant and developed algorithms are verified via real-time microgrid test bench based on hardware-in-the-loop simulation systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권5호
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• pp.2299-2318
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• 2019

Location-aware networks are of great importance for both civil lives and military applications. Methods based on line-of-sight (LOS) measurements suffer sever performance loss in harsh environments such as indoor scenarios, where sensors can receive both LOS and non-line-of-sight (NLOS) measurements. In this paper, we propose a data association (DA) process based on the expectation maximization (EM) algorithm, which enables us to exploit multipath components (MPCs). By setting the mapping relationship between the measurements and scatters as a latent variable, coefficients of the Gaussian mixture model are estimated. Moreover, considering the misalignment of sensor position, we propose a space-alternating generalized expectation maximization (SAGE)-based algorithms to jointly update the target localization and sensor position information. A two dimensional (2-D) circularly symmetric Gaussian distribution is employed to approximate the probability density function of the sensor's position uncertainty via the minimization of the Kullback-Leibler divergence (KLD), which enables us to calculate the expectation step with low computational complexity. Moreover, a distributed implementation is derived based on the average consensus method to improve the scalability of the proposed algorithm. Simulation results demonstrate that the proposed centralized and distributed algorithms can perform close to the Monte Carlo-based method with much lower communication overhead and computational complexity.

• 한국전산구조공학회논문집
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• 제16권4호
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• pp.407-417
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• 2003

최근 구조최적화분야에서 활발하게 사용되고 있는 유전알고리즘은 해집단을 운용하기 때문에, 많은 반복수와 적응도 평가를 위하여 해집단의 수에 해당하는 구조해석을 필요로 하며, 또한 교배율과 돌연변이율 등의 파라미터에 따라 알고리즘의 성능이 변화하므로 문제에, 따라 적합한 파라미터 설정이 필요한 근본적인 단점을 지니고 있다. 본 연구에서는 기존 유전알고리즘의 단점을 극복할 수 있는 복합유전알고리즘을 마이크로유전알고리즘과 단순유전알고리즘을 결합한 형식으로 그리고, 최적화에 요구되는 연산을 다수의 개인용 컴퓨터에서 동시에 분산하여 수행할 수 있는 고성능 분산 복합유전알고리즘으로 개발하였다. 개발된 알고리즘은 철골 가새골조 구조물의 최소중량설계에 적용하여 그 성능을 평가하였다.

• 한국통신학회논문지
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• 제37A권10호
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• pp.865-875
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• 2012

본 논문은 포트 당 일정 파워 제약을 전제한 상황에서, 다중 안테나를 장착한 분산 안테나 (distributed antenna: DA) 포트를 갖는 분산 안테나 시스템 (distributed antenna system: DAS)의 안테나 위치 설계 방법을 분석한다. 안테나 위치의 설계를 위해 복잡하게 셀 당 평균 ergodic sum rate를 최대화하는 대신, 본 논문에서는 단일 셀 상황에서는 signal-to-noise ratio (SNR) 기댓값의 lower bound에, 그리고 이중 셀 상황에서는 signal-to-leakage ratio (SLR) 기댓값의 lower bound에 각각 초점을 맞춘다. 단일 셀 상황의 경우, 기존의 반복적 알고리즘에 비해 SNR criterion의 최적화 문제는 닫힌 형태 (closed-form)의 솔루션을 제공한다. 또한, 이중 셀 상황에선 gradient ascent 방법을 이용한 알고리즘을 제안하여 SLR criterion의 최적화 솔루션을 도출한다.

• Journal of Communications and Networks
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• 제16권4호
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• pp.436-446
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• 2014

The high intensity of research and modeling in fields of mathematics, physics, biology and chemistry requires new computing resources. For the big computational complexity of such tasks computing time is large and costly. The most efficient way to increase efficiency is to adopt parallel principles. Purpose of this paper is to present the issue of parallel computing with emphasis on the analysis of parallel systems, the impact of communication delays on their efficiency and on overall execution time. Paper focuses is on finite algorithms for solving systems of linear equations, namely the matrix manipulation (Gauss elimination method, GEM). Algorithms are designed for architectures with shared memory (open multiprocessing, openMP), distributed-memory (message passing interface, MPI) and for their combination (MPI + openMP). The properties of the algorithms were analytically determined and they were experimentally verified. The conclusions are drawn for theory and practice.

• International Journal of Computer Science & Network Security
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• 제24권4호
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• pp.170-178
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• 2024

Through the growth of the fifth-generation networks and artificial intelligence technologies, new threats and challenges have appeared to wireless communication system, especially in cybersecurity. And IoT networks are gradually attractive stages for introduction of DDoS attacks due to integral frailer security and resource-constrained nature of IoT devices. This paper emphases on detecting DDoS attack in wireless networks by categorizing inward network packets on the transport layer as either "abnormal" or "normal" using the integration of machine learning algorithms knowledge-based system. In this paper, deep learning algorithms and CNN were autonomously trained for mitigating DDoS attacks. This paper lays importance on misuse based DDOS attacks which comprise TCP SYN-Flood and ICMP flood. The researcher uses CICIDS2017 and NSL-KDD dataset in training and testing the algorithms (model) while the experimentation phase. accuracy score is used to measure the classification performance of the four algorithms. the results display that the 99.93 performance is recorded.

• 센서학회지
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• 제28권5호
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• pp.277-283
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• 2019

In this paper, we propose a distributed fusion estimation for sensor networks using a receding horizon strategy. Communication channels were modelled as Markov jump systems, and a posterior probability distribution for communication channel characteristics was calculated and incorporated into the filter to allow distributed fusion estimation to handle path loss observation situations automatically. To implement distributed fusion estimation, a Kalman-Consensus filter was then used to obtain the average consensus, based on the estimates of sensors randomly distributed across sensor networks. The advantages of the proposed algorithms were then verified using a large-scale sensor network example.

• International Journal of Computer Science & Network Security
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• 제23권5호
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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.

• 한국정보과학회논문지:데이타베이스
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• 제37권5호
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• pp.228-237
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• 2010

고차원 데이터에 대한 다양한 색인 구조가 제안되어 왔음에도 불구하고, 인터넷 서비스로서 이미지 및 동영상의 내용 기반 검색을 지원하기 위해서는 고확장성 지원 및 k-최근접점 검색 성능 향상을 지원하는 새로운 고차원 데이터의 색인 구조가 절실히 요구된다. 이에 우리는 다중 컴퓨팅 노드를 바탕으로 구축되는 분산 색인 구조로 분산 벡터 근사 트리(Distributed Vector Approximation-tree)를 제안한다. 분산 벡터 근사 트리는 대용량의 고차원 데이터로부터 추출한 샘플 데이터를 바탕으로 hybrid spill-tree를 구축하고, hybrid spill-tree외 말단 노드 각각에 분산 컴퓨팅 노드를 매핑하여 VA-file용 구축하는 두 레벨의 분산 색인 구조이다. 우리는 다중 컴퓨팅 노드들 상에 구축된 분산 벡터 근사 트리를 바탕으로 병렬 k-최근접점 검색을 수행함으로써 검씩 성능을 향상시킨다. 본 논문에서는 서로 다른 분포의 데이터 집합을 바탕으로 한 성능 시험 결과를 통하여, 분산 벡터 근사 트리가 기존의 고확장성을 지원하는 색인 구조와 비교하여 검색 정확도에 대한 손실 없이 더 빠른 k-최근접점 검색을 수행함을 보인다.