• Title/Summary/Keyword: Concerning Solution

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Ice Marking Pattern of Flowing Organic Water Solution in a Horizontal Cooled Tube (수평냉각관내에서 유동하는 유기수용액의 제빙형태)

  • 박기원
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.5
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    • pp.52-57
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    • 2000
  • Recently large capacity of electric equipment and increasing in atomic power generation are shown. One of the reason is shortage of the electric power supply for air conditioning load during summer. And every consumer is concerning about economical refrigeration and air conditioning system to decreases electric power consumption and decrease in global warming. For these necessities, ice making thermal storage system is required. Therefore, in this paper, the possibility of continuous slurry ice making using flowing organic water solution in cooled circular tube has been investigated. The experiments was carried out under some parameters of concentration and velocity of water solution, temperature of cooled tube wall, and control pressure in tube, As a result, four types of operating conditions in the pipe, that was supercooling, continuous ice making, intermittent ice making and ice blockage, were classified . And it was found that the critical condition for continuous ice making was acquired as a function of these experimental parameters.

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Characteristic Analysis of Axial-gap Motor using Magnetic Charge (Magnetic charge를 이용한 Axial-gap 전동기의 특성해석)

  • Lee, Sang-Ho;Kim, Do-Jin;Hong, Jung-Pyo
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.997-998
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    • 2007
  • This paper deals with analytical solution concerning the image method using the magnetic charge instead of 3D FEA(finite element analysis) in the slotless single air-gap motor. The theory of analytical method and the design procedures are introduced. The reliability and validity of proposed analytical solution are verified through the comparison with the results of commercial 3D FE software. In addition, calculation time between proposed analytical solution and 3D FEA is compared. Finally, characteristics, such as Back-EMF and phase resistance, between calculated and experimental results are compared. From the verification with 3D FEA and experimental results, it is proved that presented analytical method provided very effective and precise results.

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A Study for the Viscous Flow of Sodium Chloride Through a Cuprophane Membrane

  • Jee Jong-Gi;Kwun Oh Cheun;Jhon Mu Shik;Ree Taikyue
    • Bulletin of the Korean Chemical Society
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    • v.3 no.1
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    • pp.23-30
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    • 1982
  • For the study of transport phenomena of an aqueous NaCl solution through a cuprophane membrane, a new apparatus was constructed. The volumc flow rate Q, the permeability coefficient U, and the permeability constant K were measured or determined by using this apparatus. The experimental temperature range was 5 to $35^{\circ}C$, and the applied pressure increments were 10 to 40 psi. By assuming that the cuprophane membrane is composed of n parallel cylindrical capillaries of circular cross-section and that the flow of the solution through the capillaries follows the Poiseulle law, the mean radius r of the capillaries and the number n of the latter in the membrane were evaluated. By using a reasonable assumption concerning the radius ${\eta}'$ of the species diffusing through the membrane, it was concluded that the contribution of the diffusive flow to the total flow rate Q is less than 10%. Thus, the Q was treated as the rate due to the viscous flow, and the viscosity ${\eta}_m$ of the solution in the membrane phase was evaluted, and it was found that ηm is nearly equal to ${\eta}_b$, the bulk viscosity of the solution. From this fact, it was concluded that in the capillaries, no change occurs in the physical state of the NaCl solution. The value of ( = 4.27 kcal/mole) and ${\Delta}Sm^{\neq}$(4.28 eu) were obtained for the viscous flow. A possible explanation was given.

Influence of Modeling Errors in the Boundary Element Analysis of EEG Forward Problems upon the Solution Accuracy

  • Kim, Do-Won;Jung, Young-Jin;Im, Chang-Hwan
    • Journal of Biomedical Engineering Research
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    • v.30 no.1
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    • pp.10-17
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    • 2009
  • Accurate electroencephalography (EEG) forward calculation is of importance for the accurate estimation of neuronal electrical sources. Conventional studies concerning the EEG forward problems have investigated various factors influencing the forward solution accuracy, e.g. tissue conductivity values in head compartments, anisotropic conductivity distribution of a head model, tessellation patterns of boundary element models, the number of elements used for boundary/finite element method (BEM/FEM), and so on. In the present paper, we investigated the influence of modeling errors in the boundary element volume conductor models upon the accuracy of the EEG forward solutions. From our simulation results, we could confirm that accurate construction of boundary element models is one of the key factors in obtaining accurate EEG forward solutions from BEM. Among three boundaries (scalp, outer skull, and inner skull boundary), the solution errors originated from the modeling error in the scalp boundary were most significant. We found that the nonuniform error distribution on the scalp surface is closely related to the electrode configuration and the error distributions on the outer and inner skull boundaries have statistically meaningful similarity to the curvature distributions of the boundary surfaces. Our simulation results also demonstrated that the accumulation of small modeling errors could lead to considerable errors in the EEG source localization. It is expected that our finding can be a useful reference in generating boundary element head models.

SHOULD PRUNING BE A PRE-PROCESSOR OF ANY LINEAR SYSTEM?

  • Sen, Syamal K.;Ramakrishnan, Suja;Agarwal, Ravi P.;Shaykhian, Gholam Ali
    • Journal of applied mathematics & informatics
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    • v.29 no.5_6
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    • pp.1337-1349
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    • 2011
  • So far as a solution of the given consistent linear system is concerned many numerical methods - both mathematically non-iterative as well as iterative - have been reported in the literature over the last couple of centuries. Most of these methods consider all the equations including linearly dependent ones in the system and obtain a solution whenever it exists. Since linearly dependent equations do not add any new information to a system concerning a solution we have proposed an algorithm that identifies them and prunes them in the process of solving the system. The pruning process does not involve row/column interchanges as in the case of Gauss reduction with partial/complete pivoting. We demonstrate here that the use of pruning as an inbuilt part of our solution process reduces computational and storage complexities and also computational error.

Development of Adoption Strategy and Guideline of Business Process Management Standards: Focusing on Business Process Execution Language (비즈니스 프로세스 관리 표준 도입 전략 및 지침 개발: 비즈니스 프로세스 실행 언어를 중심으로)

  • Kim, Dong-Soo
    • Journal of Information Technology Services
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    • v.5 no.2
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    • pp.107-123
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    • 2006
  • The objectives of this study is to develop a strategy for the adoption of BPM(Business Process Management) standards and an implementation guideline of the BPM standard for BPM solution developers focusing on BPEL(Business Process Execution Language) which is regarded as the most important BPM standard. In the heterogeneous and distributed IT environments, every type of enterprise software requires standards to enhance interoperability. BPMS(Business Process Management System), which is a type of enterprise software requires BPM standards such as BPEL(Business Process Execution Language), BPMN(Business Process Modeling and Notation), BPQL(Business Process Query Language) and so on to achieve multi-system interoperability and component interoperability with their BPM solutions. It is quite helpful to provide the adoption strategy concerning BPM standards for each type of BPM solution vendors who need the BPM standards. Since the BPEL is conceived as the most important BPM standard and widely adopted by many BPM vendors, we have proposed a reference architecture for BPEL implementation and also developed the detail implementation guideline of core components of the BPM system supporting the BPEL standard. Using the strategy and implementation guideline proposed in this work, BPM solution vendors can establish their own standard adoption strategy and they can also develop their BPM solutions supporting the BPM standards more efficiently.

Free vibration of Levy-type rectangular laminated plates using efficient zig-zag theory

  • Behera, Susanta;Kumari, Poonam
    • Advances in Computational Design
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    • v.3 no.3
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    • pp.213-232
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    • 2018
  • First time, an exact solution for free vibration of the Levy-type rectangular laminated plate is developed considering the most efficient Zig-Zag theory (ZIGT) and third order theory (TOT). The plate is subjected to hard simply supported boundary condition (Levy-type) along x axis. Using the equilibrium equations and the plate constitutive relations, a set of 12 m first order differential homogenous equations are obtained, containing displacements and stress resultant as primary variables. The natural frequencies of a single-layer isotropic, multi-layer composites and sandwich plates are tabulated for three values of length-to-thickness ratio (S) and five set of boundary conditions and further assessed by comparing with existing literature and recently developed 3D EKM (extended Kantorovich method) solution. It is found that for the symmetric composite plate, TOT produces better results than ZIGT. For antisymmetric and sandwich plates, ZIGT predicts the frequency for different boundary conditions within 3% error with respect to 3D elasticity solution while TOT gives 10% error. But, ZIGT gives better predictions than the TOT concerning the displacement and stress variables.

NEW RESULT CONCERNING MEAN SQUARE EXPONENTIAL STABILITY OF UNCERTAIN STOCHASTIC DELAYED HOPFIELD NEURAL NETWORKS

  • Bai, Chuanzhi
    • Bulletin of the Korean Mathematical Society
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    • v.48 no.4
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    • pp.725-736
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    • 2011
  • By using the Lyapunov functional method, stochastic analysis, and LMI (linear matrix inequality) approach, the mean square exponential stability of an equilibrium solution of uncertain stochastic Hopfield neural networks with delayed is presented. The proposed result generalizes and improves previous work. An illustrative example is also given to demonstrate the effectiveness of the proposed result.

The plant fault diagnostic system of the using fuzzy FTA (퍼지 FTA를 이용한 설비고장진단 시스템)

  • 박주식;김길동;박상민
    • Proceedings of the Safety Management and Science Conference
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    • 2000.05a
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    • pp.207-215
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    • 2000
  • This study deals with the application of knowledge-engineering and a methodology for the assessment & measurement of reliability, availability, maintainability, and safety of industrial systems using fault-tree representation. A fuzzy methodology for fault-tree evaluation seems to be an alternative solution to overcome the drawbacks of the conventional approach(insufficient information concerning the relative frequences of hazard events). To improve the quality of results, the membership functions must be approximated based on heuristic considerations. The purpose of this Is to describe the knowlwdge engineering approach, directed to integrate the various sources of knowledge involved in a FTA.

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LQG/LTR methods for systems with input delay (입력에 시간지연이 있는 시스템에 대한 LQG/LTR 기법)

  • 권욱현;이상정
    • 제어로봇시스템학회:학술대회논문집
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    • 1986.10a
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    • pp.356-361
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    • 1986
  • This paper presents robustness properties of LQ regulators for input-delayed systems. Using frequency-domain representations, the Kalman inequality concerning the return-difference matrix is derived. The stability margins of LQ regulators are investigated using the Kalman inequality when the open-loop system is stable. In order to obtain stability margins a upper bound of the solution of LQ Riccati equations is derived. Finally, the LQG/LTR method to improve the robustness of LQG regulators is obtained and illustrated with an example.

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