• Title/Summary/Keyword: Describing Function Method

Search Result 149, Processing Time 0.025 seconds

Drift Forces on a Freely-Floating Sphere in Water of Finite Depth(I) -Momentum Theorem Method- (유한수심(有限水深)의 해상(海上)에서 규칙파(規則波)에 놓인 구(球)에 작용(作用)하는 표류력(漂流力)(I) -운동량(運動量) 이론(理論) 방법(方法)-)

  • H.S.,Choi;T.M.,Oh
    • Bulletin of the Society of Naval Architects of Korea
    • /
    • v.20 no.4
    • /
    • pp.33-40
    • /
    • 1983
  • The drift force acting on a freely-floating sphere in water of finite depth is studied within the framework of a linear potential theory. A velocity potential describing fluid motion is determined by distribution pulsating sources and dipoles on the immersed surface of the sphere. Upon knowing values of the potential, hydrodynamic forces are evaluated by integrating pressures over the immersed surface of the sphere. The motion response of the sphere in water of finite depth is obtained by solving the equation of motion. From these results, the drift force on the sphere is evaluated by the momentum theorem, in which a far-field velocity potential is utilized in forms of Kochin function. The drift force coefficient Cdr of a fixed sphere increases monotononically with non-dimensional wave frequency ${\sigma}a$. On the other hand, in freely-floating case, the Cdr has a peak value at ${\sigma}a$ of heave resonance. The magnitude of the drift force coefficient Cdr in the case of finite depth is different form that for deep water, but the general tendency seems to be similar in both cases. It is to note that Cdr is greater than 1.0 when non-dimensional water depth d/a is 1.5 in the case of freely-floating sphere.

  • PDF

Estimating Leaching of Nutrients and Pesticides in Agricultural Lands -A Perferential Flow Model- (농경지의 비료, 농약의 지하유실량 추정 -Preferential 흐름모형-)

  • 이남호;타모스틴후이스
    • Magazine of the Korean Society of Agricultural Engineers
    • /
    • v.39 no.2
    • /
    • pp.62-73
    • /
    • 1997
  • The application of nutrients and pesticides to agricultural lands has been reported to contribute to groundwater contamination, which can be explained by preferential flow in lieu of convective-dispersive flow. An one-dimensional numerical model depicting preferential water and solute movement was modified to describe multi-layer flows. The model is based on a piecewise linear conductivity function. By combining conservation of mass and Darcy's law and using the method of characteristics a solution is obtained for water flow in which water moves at distinct velocities in different flow regions instead of an average velocity for the whole profile. The model allows transfer ofqr solutes between pore groups. The transfer is characterized by assuming mixing coefficients. The model was applied to undisturbed soil columns and an experiment site with structured sandy clay loam soil. Chloride, bromide, and 2, 4-D were used as tracers. Simulated solutes concentrations were in good agreement with the soil column data and field data in which preferential flow of solute is significant. The proposed model is capable of describing preferential solute transport under laboratory and field conditions.

  • PDF

Informatics Network Representation Using Probabilistic Graphical Models of Network Genetics (유전자 네트워크에서 확률적 그래프 모델을 이용한 정보 네트워크 추론)

  • Ra Sang-Dong;Park Dong-Suk;Youn Young-Ji
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.10 no.8
    • /
    • pp.1386-1392
    • /
    • 2006
  • This study is a numerical representative modelling analysis for applying the process that unravels networks between cells in genetics to WWW of informatics. Using the probabilistic graphical model, the insight from the data describing biological networks is used for making a probabilistic function. Rather than a complex network of cells, we reconstruct a simple lower-stage model and show a genetic representation level from the genetic based network logic. We made probabilistic graphical models from genetic data and extends them to genetic representation data in the method of network modelling in informatics.

Informatics Network Representation Between Cells Using Probabilistic Graphical Models (확률적 그래프 모델을 이용한 세포 간 정보 네트워크 추론)

  • Ra, Sang-Dong;Shin, Hyun-Jae;Cha, Wol-Suk
    • KSBB Journal
    • /
    • v.21 no.4
    • /
    • pp.231-235
    • /
    • 2006
  • This study is a numerical representative modeling analysis for the application of the process that unravels networks between cells in genetics to web of informatics. Using the probabilistic graphical model, the insight from the data describing biological networks is used for making a probabilistic function. Rather than a complex network of cells, we reconstruct a simple lower-stage model and show a genetic representation level from the genetic based network logic. We made probabilistic graphical models from genetic data and extends them to genetic representation data in the method of network modeling in informatics

Study on the Time Improvement of Interrupt Program by SFC (SFC언어에서 인터럽트 프로그램 시간개선에 관한 연구)

  • You, Jeong-Bong
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.14 no.10
    • /
    • pp.5134-5139
    • /
    • 2013
  • Ladder Diagram(LD) or Sequential Function Chart(SFC) is used for the design of complex modern control system with Programmable logic controller(PLC). LD is the most widely utilized among PLC standard language. But recently, SFC is used frequently. SFC is very easy to grasp the sequential flow of control logic but is difficult for describing combinational logic. When the interrupt factor is occurred, the main program is stopped. And after the interrupt program is completed, the main program is restart. Therefore the more complex the interrupt program, the main program is interrupted downtime will be that much longer. In this paper, we propose the method for interrupt implementation without the dwell time of the main program by SFC language and confirm his feasibility through the simulation.

A Study on the Database Structure for Utilizing Classical Literature Knowledge (고문헌 지식활용을 위한 DB구조에 관한 고찰)

  • Woo, Dong-Hyun;Kim, Ki-Wook;Lee, Byung-Wook
    • The Journal of Korean Medical History
    • /
    • v.33 no.2
    • /
    • pp.89-104
    • /
    • 2020
  • The purpose of this research is to build a database structure that can be useful for evidence-based medical practices by constructing the knowledge related to oriental medicine in the classical literature knowledge in a form that can utilize new forms of information technology. As a method, "database" is used as a keyword to search published studies in the field of oriental medicine, research is conducted on classic literature knowledge, and studies describing the contents of the data structure are found and analyzed. In conclusion, the original text DB for the preservation of the original texts and the presentation of the supporting texts should include 'Contents Text', 'Tree Structure', 'Herbal Structure', 'Medicine Manufacture', and 'Disease Structure' tables. In order to search, calculate, and automatically extract expressions written in the original text of the old literature, the tool DB should include 'Unit List', 'Capacity Notation List', 'CUI', 'LUI', and 'SUI' tables. In addition, In order to manage integrated knowledge such as herbal, medicine, acupuncture, disease, and literature, and to implement a search function such as comparison of similarity of control composition, the knowledge DB must contain 'dose-controlled medicine name', 'dose-controlled medicine composition', 'relational knowledge', 'knowledge structure', and 'computational knowledge' tables.

Probabilistic model for bio-cells information extraction (바이오 셀 정보 추출을 위한 확률 모델)

  • Seok, Gyeong-Hyu;Park, Sung-Ho
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.6 no.5
    • /
    • pp.649-656
    • /
    • 2011
  • This study is a numerical representative modelling analysis for applying the process that unravels networks between cells in genetics to Network of informatics. Using the probabilistic graphical model, the insight from the data describing biological networks is used for making a probabilistic function. Rather than a complex network of cells, we reconstruct a simple lower-stage model and show a genetic representation level from the genetic based network logic. We made probabilistic graphical models from genetic data and extend them to genetic representation data in the method of network modelling in informatics.

Molecular Simulations and Conformational Studies of Fucoseα1-3)Gal(β1-X)GlcNAc where X=3, 4, or 6 Oligosaccharides

  • Yoo, Eun-Sun;Yoon, In-Mo
    • Bulletin of the Korean Chemical Society
    • /
    • v.29 no.9
    • /
    • pp.1755-1760
    • /
    • 2008
  • Energy minimization and conformational studies of molecular ions generated by ESI (electrospray ionization) tandem mass spectrometry (MS/MS) can be used for the discrimination of stereoisomeric permethylated and sodium cationized trisaccharides. Sets of fucose-containing trisaccharides having different internal and terminal linkages have been synthesized to analyze the reducing terminal linkage positions using BT and IT fusion approaches. A detailed investigation has been undertaken on the conformational behaviors of four trisaccharide fragments from human milk and blood group determinants of Type 1 and Type 2, namely Fuc($\alpha$1- 3)Gal($\beta$1-3)GalNAc and Fuc($\alpha$1-3)Gal($\beta$1-X)GlcNAc where X = 3, 4 and 6 using molecular modeling methods. Three dimensional rigid and adiabatic phi-psi-energy maps (Surfer program) describing the energy as a function of rotation around corresponding glycosidic linkages were calculated by SYBYL molecular modeling and MM4 force field programs conjunction with cleavage energies of ESI MS/MS for the side group orientations. This approach predicted conformational behaviors exhibited by isomer saccharides for future applications on biologically active glycoconjugates and to exploit a faster method of synthesizing a series of structural isomeric oligosaccharides.

Improvement of Memory Efficiency in Hierarchical Control Structure described by SFC (SFC로 기술(記述)된 계층제어 구조에서 메모리 효율 향상)

  • You, Jeong-Bong
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.7 no.2
    • /
    • pp.126-130
    • /
    • 2006
  • Programmable Logic Controller(PLC) is the most widely utilized and plays an important role in industrial control system. Sequential Function Chart(SFC) is a graphic language which is suitable for describing a sequential control logic in discrete control system. We can design a distribute control construction and a hierarchical control construction in process control system described by SFC. In hierarchical control structure, we construct each subsystems to synchronize a synchronous signal between subsystems, and the command system gives and takes a synchronous signal with subsystems. Therefore, the system has a low memory efficiency and a low system performance. In this paper, we propose the method that improved the efficiency of memory in hierarchical control construction, and confirm its feasibility through an actual example.

  • PDF

The Development of Compensated Bang-Bang Current Controller for Travel Motor of Industry Electrical Vechicle (산업용 전기차량의 주행 모터용 보상된 Bang-Bang 전류제어기 개발)

  • Chen, Young-Shin;Jung, Young-Il;Bae, Jong-Il;Lee, Man-Hyung
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.16 no.9
    • /
    • pp.34-40
    • /
    • 1999
  • In order to establish the design technique of the robust current controller in d.c series wound motor driver system, this paper proposes a method of the compensated Bang-Bang current control using d.c series wound motor driver system under the improperly variable load to get minimum time for the torque control. The compensated Bang-Bang current controller structure is simpler than that of PID plus Bang-Bang controller. This paper shows that a general 16 bits microprocessor is efficiently used to implement such an algorithm. The calculation time of software is extremely small when compared with that of conventional PID plus Bang-Bang controller. Both nonlinear operating characteristics of digital switching elements and describing function methods are used for the analysis and synthesis. Real-time implementation of the compensated Bang-Bang current controller is achieved. The concept of design strategy of the control and the PWM waveform generation algorithms are presented in this paper.

  • PDF