• Title/Summary/Keyword: EA performance

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Numerical Integration-based Performance Analysis of Cross-eye Jamming Algorithm through Amplitude Ratio Perturbation (진폭비 섭동에 의한 cross-eye 재밍에 대한 수치적분 기반 성능분석)

  • Kim, Je-An;Choi, Yoon-Ju;Lee, Joon-Ho
    • Journal of the Korea Convergence Society
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    • v.12 no.12
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    • pp.59-64
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    • 2021
  • This paper deals with the performance analysis of the jamming effect of cross-eye when the difference between the real amplitude ratio and the nominal amplitude ratio due to mechanical defects is modeled as a random variable with a normal distribution. We propose how to evaluate mean square difference (MSD) obtained using a numerical integration-based approach. The MSD obtained by the proposed method is closer to non-approximated Monte-Carlo simulation-based MSD than the analytic MSD calculated using the first-order Taylor approximation and the second-order Taylor approximation. It is shown that, based on the numerical integration, the effect of amplitude ratio perturbation on the cross-eye jamming performance can be evaluated without going through the computationally intensive Monte-Carlo method.

Glass Dissolution Rates From MCC-1 and Flow-Through Tests

  • Jeong, Seung-Young
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2004.06a
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    • pp.257-258
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    • 2004
  • The dose from radionuclides released from high-level radioactive waste (HLW) glasses as they corrode must be taken into account when assessing the performance of a disposal system. In the performance assessment (PA) calculations conducted for the proposed Yucca Mountain, Nevada, disposal system, the release of radionuclides is conservatively assumed to occur at the same rate the glass matrix dissolves. A simple model was developed to calculate the glass dissolution rate of HLW glasses in these PA calculations [1]. For the PA calculations that were conducted for Site Recommendation, it was necessary to identify ranges of parameter values that bounded the dissolution rates of the wide range of HLW glass compositions that will be disposed. The values and ranges of the model parameters for the pH and temperature dependencies were extracted from the results of SPFT, static leach tests, and Soxhlet tests available in the literature. Static leach tests were conducted with a range of glass compositions to measure values for the glass composition parameter. The glass dissolution rate depends on temperature, pH, and the compositions of the glass and solution, The dissolution rate is calculated using Eq. 1: $rate{\;}={\;}k_{o}10^{(ph){\eta})}{\cdot}e^{(-Ea/RT)}{\cdot}(1-Q/K){\;}+{\;}k_{long}$ where $k_{0},\;{\eta}$ and Eaare the parameters for glass composition, pH, $\eta$ and temperature dependence, respectively, and R is the gas constant. The term (1-Q/K) is the affinity term, where Q is the ion activity product of the solution and K is the pseudo-equilibrium constant for the glass. Values of the parameters $k_{0},\;{\eta}\;and\;E_{a}$ are the parameters for glass composition, pH, and temperature dependence, respectively, and R is the gas constant. The term (1-Q/C) is the affinity term, where Q is the ion activity product of the solution and K is the pseudo-equilibrium constant for the glass. Values of the parameters $k_0$, and Ea are determined under test conditions where the value of Q is maintained near zero, so that the value of the affinity term remains near 1. The dissolution rate under conditions in which the value of the affinity term is near 1 is referred to as the forward rate. This is the highest dissolution rate that can occur at a particular pH and temperature. The value of the parameter K is determined from experiments in which the value of the ion activity product approaches the value of K. This results in a decrease in the value of the affinity term and the dissolution rate. The highly dilute solutions required to measure the forward rate and extract values for $k_0$, $\eta$, and Ea can be maintained by conducting dynamic tests in which the test solution is removed from the reaction cell and replaced with fresh solution. In the single-pass flow-through (PFT) test method, this is done by continuously pumping the test solution through the reaction cell. Alternatively, static tests can be conducted with sufficient solution volume that the solution concentrations of dissolved glass components do not increase significantly during the test. Both the SPFT and static tests can ve conducted for a wide range of pH values and temperatures. Both static and SPFt tests have short-comings. the SPFT test requires analysis of several solutions (typically 6-10) at each of several flow rates to determine the glass dissolution rate at each pH and temperature. As will be shown, the rate measured in an SPFt test depends on the solution flow rate. The solutions in static tests will eventually become concentrated enough to affect the dissolution rate. In both the SPFt and static test methods. a compromise is required between the need to minimize the effects of dissolved components on the dissolution rate and the need to attain solution concentrations that are high enough to analyze. In the paper, we compare the results of static leach tests and SPFT tests conducted with simple 5-component glass to confirm the equivalence of SPFT tests and static tests conducted with pH buffer solutions. Tests were conducted over the range pH values that are most relevant for waste glass disssolution in a disposal system. The glass and temperature used in the tests were selected to allow direct comparison with SPFT tests conducted previously. The ability to measure parameter values with more than one test method and an understanding of how the rate measured in each test is affected by various test parameters provides added confidence to the measured values. The dissolution rate of a simple 5-component glass was measured at pH values of 6.2, 8.3, and 9.6 and $70^{\circ}C$ using static tests and single-pass flow-through (SPFT) tests. Similar rates were measured with the two methods. However, the measured rates are about 10X higher than the rates measured previously for a glass having the same composition using an SPFT test method. Differences are attributed to effects of the solution flow rate on the glass dissolution reate and how the specific surface area of crushed glass is estimated. This comparison indicates the need to standardize the SPFT test procedure.

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Biguanide-Functionalized Fe3O4/SiO2 Magnetic Nanoparticles: An Efficient Heterogeneous Organosuperbase Catalyst for Various Organic Transformations in Aqueous Media

  • Alizadeh, Abdolhamid;Khodaei, Mohammad M.;Beygzadeh, Mojtaba;Kordestani, Davood;Feyzi, Mostafa
    • Bulletin of the Korean Chemical Society
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    • v.33 no.8
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    • pp.2546-2552
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    • 2012
  • A novel biguanide-functionalized $Fe_3O_4/SiO_2$ magnetite nanoparticle with a core-shell structure was developed for utilization as a heterogeneous organosuperbase in chemical transformations. The structural, surface, and magnetic characteristics of the nanosized catalyst were investigated by various techniques such as transmission electron microscopy (TEM), powder X-ray diffraction (XRD), vibrating sample magnetometry (VSM), elemental analyzer (EA), thermogravimetric analysis (TGA), $N_2$ adsorption-desorption (BET and BJH) and FT-IR. The biguanide-functionalized $Fe_3O_4/SiO_2$ nanoparticles showed a superpara-magnetic property with a saturation magnetization value of 46.7 emu/g, indicating great potential for application in magnetically separation technologies. In application point of view, the prepared catalyst was found to act as an efficient recoverable nanocatalyst in nitroaldol and domino Knoevenagel condensation/Michael addition/cyclization reactions in aqueous media under mild condition. Additionally, the catalyst was reused six times without significant degradation in catalytic activity and performance.

Design and Development of an Alarm Gathering Interface Equipment for ATM Switching System (ATM 시스템 경보 취합 장치 설계 및 개발)

  • Yang, Chung-Ryeol;Kim, Jin-Tae
    • The Transactions of the Korea Information Processing Society
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    • v.3 no.7
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    • pp.1845-1857
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    • 1996
  • An alarm gathering interface equipment has been developed to collect the hardware failure activities in 1$1, 024\times1, 024$ ATM switching system. The equipment use 8-bit microprocessor and ELA-232C port, and is fabricated in a single board, which called Alarm Gathering Interface board Assembly(AGIA). It is programmed to ensure flexibility in modification and expansion of the system capability. The performance is successfully proved through communication test with hardware blocks or modules consisting a ATM switching system, these techniques can be used to develop operation and maintenance functions for more superior ATM switching system in the near future. we additionally have presented some items for further study on alarm subsystem often ATM switching system.

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Effect of Chemical Treatment on Performance Behaviors of PtRu/GNFs Catalysts for DMFCs (직접 메탄올 연료전지용 PtRu/GNF 성능에 대한 화학적 처리의 영향)

  • Park, Soo-Jin;Park, Jeong-Min
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.369-372
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    • 2009
  • In the present study, the effect of chemical treatment on graphite nanofibers (GNFs) supports with various concentrated nitric acids was investigated for methanol oxidation. To optimize the electrocatalytic activity, PtRu catalysts were deposited on GNF supports by impregnation method. The surface and structural properties of the GNF supports were characterized by X-ray photoelectron spectroscopy (XPS), element analyzer (EA), and X-ray diffraction (XRD). The morphology of the catalysts was observed by means of transmission electron microscopy (TEM). The electrocatalytic activity of PtRu/GNF catalysts was investigated by cyclic voltammetry measurement. As a result, the oxygen functional groups were introduced on the GNF supports and were gradually increased with increasing of concentrated nitric acid, causing the smaller particle size and higher loading level. And the electrocatalytic activity of the catalysts for methanol oxidation was gradually improved. Consequently, it was found that chemical treatments could influence on surface properties of the carbon supports, resulting in enhancing the electrocatalytic activity of the catalysts for DMFCs.

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A Symbiotic Evolutionary Algorithm for Multi-objective Optimization (다목적 최적화를 위한 공생 진화알고리듬)

  • Shin, Kyoung-Seok;Kim, Yeo-Keun
    • Journal of the Korean Operations Research and Management Science Society
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    • v.32 no.1
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    • pp.77-91
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    • 2007
  • In this paper, we present a symbiotic evolutionary algorithm for multi-objective optimization. The goal in multi-objective evolutionary algorithms (MOEAs) is to find a set of well-distributed solutions close to the true Pareto optimal solutions. Most of the existing MOEAs operate one population that consists of individuals representing the entire solution to the problem. The proposed algorithm has a two-leveled structure. The structure is intended to improve the capability of searching diverse and food solutions. At the lower level there exist several populations, each of which represents a partial solution to the entire problem, and at the upper level there is one population whose individuals represent the entire solutions to the problem. The parallel search with partial solutions at the lower level and the Integrated search with entire solutions at the upper level are carried out simultaneously. The performance of the proposed algorithm is compared with those of the existing algorithms in terms of convergence and diversity. The optimization problems with continuous variables and discrete variables are used as test-bed problems. The experimental results confirm the effectiveness of the proposed algorithm.

Temperature Control of a CSTR using Fuzzy Gain Scheduling (퍼지 게인 스케쥴링을 이용한 CSTR의 온도 제어)

  • Kim, Jong-Hwa;Ko, Kang-Young;Jin, Gang-Gyoo
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.9
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    • pp.839-845
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    • 2013
  • A CSTR (Continuous Stirred Tank Reactor) is a highly nonlinear process with varying parameters during operation. Therefore, tuning of the controller and determining the transition policy of controller parameters are required to guarantee the best performance of the CSTR for overall operating regions. In this paper, a methodology employing the 2DOF (Two-Degree-of-Freedom) PID controller, the anti-windup technique and a fuzzy gain scheduler is presented for the temperature control of the CSTR. First, both a local model and an EA (Evolutionary Algorithm) are used to tune the optimal controller parameters at each operating region by minimizing the IAE (Integral of Absolute Error). Then, a set of controller parameters are expressed as functions of the gain scheduling variable. Those functions are implemented using a set of "if-then" fuzzy rules, which is of Sugeno's form. Simulation works for reference tracking, disturbance rejecting and noise rejecting performances show the feasibility of using the proposed method.

A Study on the Response Characteristics Depending on Service Life of Ionization Smoke Detector (이온화식연기감지기의 사용기간에 따른 응답특성 연구)

  • Baek, Won-Don;Kim, Shi-Kuk;Ok, Kyung-Jea;Lee, Chun-Ha;Jee, Seung-Wook
    • Fire Science and Engineering
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    • v.22 no.4
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    • pp.61-64
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    • 2008
  • This paper studied on the response characteristics depending on service life of ionization smoke detector. The experimental samples used ionization smoke detectors (360 EA) for over 5 years which were influenced by environment set up with fire objects. The experimental method performed operate and non-operate test according to 'Type Approval and Technical Regulation of Detector (KOFEIS 0301)', for estimate the response characteristics of ionization smoke detector depending on service life. The results showed that their response characteristics were rapidly decreasing when the longer their using period. Accordingly, it is desirable that ionization smoke detector has to be changed for early fire detection when passed their service life.

Effect of Blowing Agents on Properties of Phenolic Foam (발포제 종류에 따른 페놀 폼의 물성 연구)

  • Jang, SaeYoon;Kim, Sangbum
    • Journal of the Korean Institute of Gas
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    • v.20 no.2
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    • pp.30-34
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    • 2016
  • In this study, we synthesized a phenol foam using a resol-type phenol resin as a research for replacing the polyurethane foam used as an insulator for cryogenic temperature, such as LNG or LPG. Foaming agents for synthesizing a phenolic foam was used HCFC-141b or n-pentane, cyclopentane, n-hexane, cyclohexane and a mixture of HFC-365mfc and HFC-227ea respectively. Cyclohexane as a blowing agent exhibited the most superior insulating performance and compressive strength. The heat resistance of polyurethane foam and phenolic foam blown by the cyclohexane, was higher than polyurethane foam.

Optimal Determination of Pipe Support Types in Flare System for Minimizing Support Cost (비용 최소화를 위한 플래어 시스템의 배관 서포트 타입 최적설계)

  • Park, Jung-Min;Park, Chang-Hyun;Kim, Tea-Soo;Choi, Dong-Hoon
    • Journal of the Society of Naval Architects of Korea
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    • v.48 no.4
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    • pp.325-329
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    • 2011
  • Floating, production, storage and offloading (FPSO) is a production facility that refines and saves the drilled crude oil from a drilling facility in the ocean. The flare system in the FPSO is a major part of the pressure relieving system for hydrocarbon processing plants. The flare system consists of a number of pipes and complicated connection systems. Decision of pipe support types is important since the load on the support and the stress in the pipe are influenced by the pipe support type. In this study, we optimally determined the pipe support types that minimized the support cost while satisfying the design constraints on maximum support load, maximum nozzle load and maximum pipe stress ratio. Performance indices included in the design constraints for a specified design were evaluated by pipe structural analysis using CAESAR II. Since pipe support types were all discrete design variables, an evolutionary algorithm (EA) was used as an optimizer. We successfully obtained the optimal solution that reduced the support cost by 27.2% compared to the initial support cost while all the design requirements were satisfied.