• Title/Summary/Keyword: Energy optimization

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Theoretical Studies of the Structures and Electronic Properties of CumSiOm+1 Clusters (m = 0 - 7) (CumSiOm+1 클러스터(m = 0 - 7)의 분자구조 그리고 전기적 특성에 관한 이론 연구)

  • Na, Ho-Hyun;Nam, Seong-Hyun;Lee, Gi-Yun;Jang, Ye-Seul;Yoon, Duck-Young;Bae, Gyun-Tack
    • Journal of the Korean Chemical Society
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    • v.60 no.4
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    • pp.239-244
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    • 2016
  • We investigated the structures and electronic properties of CumSiOm+1 clusters with m = 0 - 7. For these clusters, we replaced a Cu atom in the copper oxide clusters with a Si atom. The B3LYP functional and LANL2DZ basis set were used for optimization of the molecular structures of all neutral and charged clusters. The bond distances, bond angles, and Mulliken charges were calculated to study the structural properties. In addition, in order to understand the electronic properties, we examined the ionization energies, electronic affinities, and second differences in energies.

Visualizing test on the pass-through and collision characteristics of coarse particles in a double blade pump

  • Tan, Minggao;Lian, Yichao;Liu, Houlin;Wu, Xianfang;Ding, Rong
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.10 no.1
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    • pp.1-8
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    • 2018
  • As the key equipment in deep ocean mining, the slurry pump suffers from wear and blocking problems. In this paper, high-speed photography technique is applied to track the movement rule of single particle of the coarse particle solid-liquid two-phase flow in a double blade slurry pump. The influences of particle diameter and particle density on the pass-through and collision characteristics of particles are analyzed as well. The results show that the average of the passing pump time first decreases and then increases when the particle diameter increases. The average of the passing pump time decreases by 22.7%, when the particle density increases from $1.09g/cm^3$ to $1.75g/cm^3$. Besides, the particle density has great influence on the location where the particle hits the tongue. Most particles of $1.09g/cm^3$ hit the tongue on the left side, while collision location of particles of $1.75g/cm^3$ is mainly on the top and at the right side of the tongue. The research can provide a basis for the optimization design of slurry pump in deep ocean mining system.

Using Genetic Algorithms for Routing Metric in Wireless Mesh Network (무선 메쉬 네트워크에서 유전 알고리즘을 이용한 라우팅 메트릭 기법)

  • Yoon, Chang-Pyo;Shin, Hyo-Young;Ryou, Hwang-Bin
    • Convergence Security Journal
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    • v.11 no.1
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    • pp.11-18
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    • 2011
  • Wireless mesh network technology with transmission speeds similar to wired and wireless technology means to build, compared with wired networks, building a more efficient network to provide convenience and flexibility. The wireless mesh network router nodes in the energy impact of the mobility is less constrained and has fewer features entail. However, the characteristics of various kinds due to network configuration settings and the choice of multiple paths that can occur when the system overhead and there are many details that must be considered. Therefore, according to the characteristics of these network routing technology that is reflected in the design and optimization of the network is worth noting. In this paper, a multi-path setting can be raised in order to respond effectively to the problem of the router node data loss and bandwidth according to traffic conditions and links to elements of the hop count evaluation by using a genetic algorithm as a workaround for dynamic routing the routing metric for wireless mesh network scheme is proposed.

Performance of Position Based Fast Fault Recovery Protocol for Industrial Bridged Ring Networks (산업용 브리지 망을 위한 위치 기반의 신속한 망 장애 복구 절차의 성능분석)

  • Seo, Ju Sang;Yoon, Chong Ho;Park, Hong Soon;Kim, Jin Uk
    • KEPCO Journal on Electric Power and Energy
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    • v.6 no.3
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    • pp.259-269
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    • 2020
  • With the proposal-agreement procedure, RSTP can reduce the network recovery time to 400 ms or less in the case of 40 bridges. While the legacy RSTP reverts the previous agreement at the bridge with the alternate port role in the ring during the fault recovery, a new position based fast fault recovery procedure is proposed in this paper to guarantee a single proposal-agreement transaction which can provide more faster recovery. By knowing the relative position of the faulty link or bridge in hops, the bridge on the middle of the ring can complete the recovery procedure without revert. The performance of proposed procedure is numerically calculated and verified by simulation and the result shows that the recovery time can be reduced up to 100 ms, which is 1/4 times of the legacy RSTP.

An Economic Feasibility Study of Wind-Diesel Hybrid Power Systems for an Island in the Yellow Sea (서해 도서지역의 풍력-디젤 하이브리드 발전에 대한 경제성 분석)

  • Lee, Tak-Kee;Nam, Yong-Yun;Kim, Jae-Dong;Han, Jeong-Woo
    • Journal of Navigation and Port Research
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    • v.35 no.5
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    • pp.381-385
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    • 2011
  • In this paper, an economic feasibility study of wind-diesel hybrid power systems for an island in the Yellow Sea, where the maximum power generation is about 500kW, was performed. For the study, annual electric load variation and wind resource data of the island were collected and analyzed. HOMER program - a typical hybrid optimization model for electric renewables including wind resource, developed by the National Renewable Energy Laboratory - was used. Wind speed and diesel price were picked out as variables for the sensitivity analysis in order to find the economic accountability for the wind-diesel hybrid power system. As the result, even though it is not feasible economically under the present condition, if mean wind speed is over 3 m/sec. or diesel price goes up to 2.4 $ per liter, the wind-diesel hybrid power system for the island becomes a prospective candidate.

Distribution System Reconfiguration Using the PC Cluster based Parallel Adaptive Evolutionary Algorithm

  • Mun Kyeong-Jun;Lee Hwa-Seok;Park June Ho;Hwang Gi-Hyun;Yoon Yoo-Soo
    • KIEE International Transactions on Power Engineering
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    • v.5A no.3
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    • pp.269-279
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    • 2005
  • This paper presents an application of the parallel Adaptive Evolutionary Algorithm (AEA) to search an optimal solution of a reconfiguration in distribution systems. The aim of the reconfiguration is to determine the appropriate switch position to be opened for loss minimization in radial distribution systems, which is a discrete optimization problem. This problem has many constraints and it is very difficult to find the optimal switch position because of its numerous local minima. In this investigation, a parallel AEA was developed for the reconfiguration of the distribution system. In parallel AEA, a genetic algorithm (GA) and an evolution strategy (ES) in an adaptive manner are used in order to combine the merits of two different evolutionary algorithms: the global search capability of GA and the local search capability of ES. In the reproduction procedure, proportions of the population by GA and ES are adaptively modulated according to the fitness. After AEA operations, the best solutions of AEA processors are transferred to the neighboring processors. For parallel computing, a PC-cluster system consisting of 8 PCs·was developed. Each PC employs the 2 GHz Pentium IV CPU, and is connected with others through switch based fast Ethernet. The new developed algorithm has been tested and is compared to distribution systems in the reference paper to verify the usefulness of the proposed method. From the simulation results, it is found that the proposed algorithm is efficient and robust for distribution system reconfiguration in terms of the solution quality, speedup, efficiency, and computation time.

A Study on the Electrochemical Synthesis of L-DOPA Using Oxidoreductase Enzymes: Optimization of an Electrochemical Process

  • Rahman, Siti Fauziyah;Gobikrishnan, Sriramulu;Indrawan, Natarianto;Park, Seok-Hwan;Park, Jae-Hee;Min, Kyoungseon;Yoo, Young Je;Park, Don-Hee
    • Journal of Microbiology and Biotechnology
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    • v.22 no.10
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    • pp.1446-1451
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    • 2012
  • Levodopa or L-3,4-dihydroxyphenylalanine (L-DOPA) is the precursor of the neurotransmitter dopamine. L-DOPA is a famous treatment for Parkinson's disease symptoms. In this study, electroenzymatic synthesis of L-DOPA was performed in a three-electrode cell, comprising a Ag/AgCl reference electrode, a platinum wire auxiliary electrode, and a glassy carbon working electrode. L-DOPA had an oxidation peak at 376 mV and a reduction peak at -550 mV. The optimum conditions of pH, temperature, and amount of free tyrosinase enzyme were pH 7, $30^{\circ}C$, and 250 IU, respectively. The kinetic constant of the free tyrosinase enzyme was found for both cresolase and catacholase activity to be 0.25 and 0.4 mM, respectively. A cyclic voltammogram was used to investigate the electron transfer rate constant. The mean heterogeneous electron transfer rate ($k_e$) was $5.8{\times}10^{-4}$ cm/s. The results suggest that the electroenzymatic method could be an alternative way to produce L-DOPA without the use of a reducing agent such as ascorbic acid.

Investigation on Oil-paper Degradation Subjected to Partial Discharge Using Chaos Theory

  • Gao, Jun;Wang, Youyuan;Liao, Ruijin;Wang, Ke;Yuan, Lei;Zhang, Yiyi
    • Journal of Electrical Engineering and Technology
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    • v.9 no.5
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    • pp.1686-1693
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    • 2014
  • In this paper, oil-paper samples composed of transformer windings were used to investigate the insulation degradation process subjected to partial discharge (PD), with artificial defects inside to simulate the PD induced insulation degradation. To determine appropriate test voltages, the breakdown time obtained through a group of accelerated electrical degradation tests under high voltages was firstly fitted by two-parameter Weibull model to acquire the average breakdown time, which was then applied to establish the inverse power law life model to choose advisable test voltages. During the electrical degradation process, PD signals were synchronously detected by an ultra-high frequency (UHF) sensor from inception to breakdown. For PD analysis, the whole degradation process was divided into ten stages, and chaos theory was introduced to analyze the variation of three chaotic parameters with the development of electrical degradation, namely the largest Lyapunov exponent, correlation dimension and Komogorov entropy of PD amplitude time series. It is shown that deterministic chaos of PD is confirmed during the oil-paper degradation process, and the obtained results provide a new effective tool for the diagnosis of degradation of oil-paper insulation subjected to PD.

Multiplication optimization technique for Elliptic Curve based sensor network security (Elliptic curve기반 센서네트워크 보안을 위한 곱셈 최적화 기법)

  • Seo, Hwa-Jeong;Kim, Ho-Won
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.8
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    • pp.1836-1842
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    • 2010
  • Sensor network, which is technology to realize the ubiquitous environment, recently, could apply to the field of Mechanic & electronic Security System, Energy management system, Environment monitoring system, Home automation and health care application. However, feature of wireless networking of sensor network is vulnerable to eavesdropping and falsification about message. Presently, PKC(public key cryptography) technique using ECC(elliptic curve cryptography) is used to build up the secure networking over sensor network. ECC is more suitable to sensor having restricted performance than RSA, because it offers equal strength using small size of key. But, for high computation cost, ECC needs to enhance the performance to implement over sensor. In this paper, we propose the optimizing technique for multiplication, core operation in ECC, to accelerate the speed of ECC.

Using Genetic Algorithms in Wireless Mesh Network Routing Protocol Design (유전 알고리즘을 이용한 무선 메쉬 네트워크에서의 라우팅 프로토콜 설계)

  • Yoon, Chang-Pyo;Ryou, Hwang-Bin
    • The KIPS Transactions:PartC
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    • v.18C no.3
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    • pp.179-186
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    • 2011
  • Wireless Mesh Network technology refers to the technology which establishes wireless network whose transmission speed is similar to that of the wire system, and provides more enhanced flexibility in the building of network, compared to the existing wired network. In addition, it has the feature of less mobility and less restriction from the energy effect. However, there follow many considerations such as system overhead in the case of setting or the selection of multi-path. Accordingly, the focus is on the design and optimization of network which can reflect this network feature and the technology to establish path. This paper suggests the methods on the programming of path in Wireless Mesh Network routing by applying the evaluation value of node service, making use of the loss rate of data, the hop count of bandwidth and link and the traffic status of node, considering the performance of link and load in the fitness evaluation function, in order to respond to the programming of multi-path effectively.