Processing math: 100%
  • Title/Summary/Keyword: Proper variables

Search Result 698, Processing Time 0.028 seconds

Development of Ultrasonic Linear Motor using Piezoelectric Ceramics (압전 초음파 선형 모터 개발)

  • Kim, Yeon-Bo;Han, Woo-Seok;Roh, Yong-Rae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2000.05b
    • /
    • pp.279-282
    • /
    • 2000
  • We have been designed and fabricated a bi-directional ultrasonic linear motor using piezoelectric ceramics. With the finite element method, we design and verify validity of the structure, and determine its optimal structure, size of design variables, material and boundary conditions for proper generation of the ultrasonic waves. Based on the design, a prototype of the ultrasonic linear motor has been fabricated and characterized, which thereby proves practical applicability of this new motor.

  • PDF

BOXES-based Cooperative Fuzzy Control for Cartpole System

  • Kwon, Sung-Gyu
    • International Journal of Fuzzy Logic and Intelligent Systems
    • /
    • v.7 no.1
    • /
    • pp.22-29
    • /
    • 2007
  • Two fuzzy controllers defined by 2 input variables cooperate to control a cartpole system in terms of balancing as well as centering. The cooperation is due to the BOXES scheme that selects one of the fuzzy controllers for each time step according to the content of box that is established through the critic of the control action by the fuzzy controllers. It is found that the control scheme is good at controlling the cartpole system so that the system is stabilized fast while the BOXES develops its ability to select proper fuzzy controller through experience.

The effects of reinforcements on the tool wear during cutting fiber-reinforced plastics (섬유강화 복합재료의 가공시 강화재가 공구마모에 미치는 영향)

  • 정용운;김주현;박주승;좌성훈
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • 1999.11a
    • /
    • pp.208-212
    • /
    • 1999
  • In the use of glass fiber reinforced plastics(GFRP), cutting is often necessary. But the most of past studies have been interested in the effect of fiber orientation on tool wear. In this study, the effects of fiber contents on tool wear were investigated experimentally. By proper selection of cutting tool, the variables are cutting speed and fiber contents of 10, 20, 30wt% with fixed feed rate and depth of cut.

  • PDF

A Study on the Variable -Structure Control Using New Switching Variables (새로운 스위칭 변수를 이용한 가변구조제어에 관한 연구)

  • 이주장;이흥규;이병일
    • Journal of the Korean Institute of Telematics and Electronics
    • /
    • v.25 no.12
    • /
    • pp.1586-1593
    • /
    • 1988
  • A new control scheme for the variable-structure control system using new time-varying switching variable is presented in this paper. It is proposed to have new algorithm for reducing the reaching time on a switching hyperplane by modifying the Morgan's algorithm. From the results of the simulation, it is concluded the proposed control algorithm yields smaller control inputs (without disturbance) and ripples (with disturbance) than that obtained by Morgan's algorithm in the steady-state. This control algorithm can be applied to proper control systems having sensitive effects on disturbances, due to the robustness.

  • PDF

Marketing Segmentation of New Product (신제품에 대한 시장세분화)

  • 김혜경
    • Journal of Korean Society of Industrial and Systems Engineering
    • /
    • v.3 no.3
    • /
    • pp.67-74
    • /
    • 1980
  • The importance of market segmentation for success in marketing new products cannot be overemphasized. The benefits of new product segmentation are many, particularly when the proper conditions for product segmentation are met. The markets for the new product can be segmented according to demographic, geographic, psychological, and product-related variables and the use of market grids. To be ultimately useful in the successful marketing of the new product, the segmentations must be of sufficient size, related to the firm's capabilities, and quantifiable.

  • PDF

A Study on the Factors of Child Care Teacher's Burnout (보육교사 조직 내 소진에 관한 연구)

  • Kim, Ji Yoon
    • Journal of Industrial Convergence
    • /
    • v.10 no.1
    • /
    • pp.13-26
    • /
    • 2012
  • The Purpose of this study was to review the theoretical background of burnout in child care teachers organization. Personal factors, Organizational factors, social factors and the factors affecting burnout I examined. The results of this study were as follows. First, Child care teachers need to be burnout to participate in Prevention programs. Second, child care teacher is required to ensure proper staffing, improved working environment through compliance with statutory working hours. Third, Various institutional arrangements required to control the variables affecting child care teachers. Fourth, Child care teacher's role to prevent excessive strategy is needed.

  • PDF

Development of Rotary Tube Piercing Machine and Parametric Study on Design Variables using Finite Element Analysis (중공 튜브 성형을 위한 만네스만 천공기의 개발 및 유한요소법을 이용한 공정변수 설계)

  • Lee, H.W.;Lee, G.A.;Kim, E.Z.;Choi, S.;Jang, B.L.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2007.05a
    • /
    • pp.364-367
    • /
    • 2007
  • Typical seamless tube production methods are an extrusion and a rotary tube piercing. The rotary piercing process is more competitive than the extrusion process form view point of productivity, quality, and flexibility. It consists of twin rolling mills, a pair of disc or flat guides, and a plug. Twin rolling mills are skewed with proper angles in two directions. A round billet is progressively fed forward and rotated due to the rotation of twin rolling mills. Internal crack initiation and growth at central area of the billet are gradually progress because of the repeating actions of tension and rotation. Design variables in the rotary piercing rolling process are the feed angle, the cross angle, the reduction ratio, and the position of plug. In this work, a rotary tube piercing machine was developed and parametric studies on design variables were carried out using finite element analysis. The Brozzo ductile fracture criterion was utilized to determine an internal crack initiation.

  • PDF

Knowledge and Compliance with Hand Hygiene by Nursing Students in Clinical Practice (병원실습 경험이 있는 간호 대학생의 손 위생 지식과 이행에 관한 연구)

  • Yoon, Eun Joo;Kim, Mi Hyang
    • The Journal of Korean Academic Society of Nursing Education
    • /
    • v.19 no.3
    • /
    • pp.455-464
    • /
    • 2013
  • Purpose: The goal of the study was to investigate nursing students' knowledge and compliance with hand hygiene to find out the variables associated with compliance with hand hygiene. Methods: The participants were 1,020 nursing college students located in Seoul, Ansan and Suncheon. The variables analyzed in this study were; hand hygiene knowledge, hand hygiene compliance, hand washing habits, hand hygiene education with emphasis in school, emphasis on hand washing and role modeling in hospital, and hand hygiene beliefs. Data were analyzed by frequency, x2-test, t-test and Pearson correlation coefficient. Results: 1. The correct answer average percentage of hand hygiene knowledge was 78.4%. 2. The average rates of hand hygiene compliance rate was 78.0% 3. Compliance rate had significant correlation with variables such as hand washing habit, hand hygiene education with emphasis in school, emphasis on hand washing and role modeling in hospital, and hand hygiene belief. Conclusion: 1. It is nessassery for nursing students to receive proper educational on hand hygiene knowledge during practices in nursing school curriculum. 2. Nurses should be encouraged to be a good mentor to nursing students on appropriate hand hygiene compliance in clinical practice.

Active Neuro-control for Seismically Excited Structure using Modal states as the Input of the Neuro-controller (모달 변위를 이용한 지진하중을 받는 구조물의 능동 신경망제어)

  • 이헌재;정형조;이종헌;이인원
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2004.04a
    • /
    • pp.423-430
    • /
    • 2004
  • A new active neuro-control strategy for seismic response reduction using modal states is proposed. In order to apply the neuro-control strategy to the given structural system it is needed to select state variables used as inputs into the neural network. If the degrees of freedom of the analytical model is large, there are so many possible combinations of the state variables. And selecting state variables is very complicated and troublesome task for the designer. In order to avoid this problem, the proposed control system adopts modal states as inputs. Since the modal states contain the information of the whole structural system's behavior, it is proper to use modal states as inputs of the neuro-controller. The simulation results show that the proposed the proposed active neuro-control strategy is quite effective to reduce seismic responses. In addition, the consuming time for training proposed neuro-controller is quite shorter than that for the conventional neuro- controller. The results of this investigation, therefore, indicate that the proposed active neuro-control strategy using modal states as the inputs could be effectively used for control seismically excited structures.

  • PDF

Optimal Reheating Condition of Semi-solid Material in Semi-solid Forging by Neural Network

  • Park, Jae-Chan;Kim, Young-Ho;Park, Joon-Hong
    • International Journal of Precision Engineering and Manufacturing
    • /
    • v.4 no.2
    • /
    • pp.49-56
    • /
    • 2003
  • As semi-solid forging (SSF) is compared with conventional casting such as gravity die-casting and squeeze casting, the product without inner defects can be obtained from semi-solid forming and globular microstructure as well. Generally, SSF consists of reheating, forging, and ejecting processes. In the reheating process, the materials are heated up to the temperature between the solidus and liquidus line at which the materials exists in the form of liquid-solid mixture. The process variables such as reheating time, reheating temperature, reheating holding time, and induction heating power has large effect on the quality of the reheated billets. It is difficult to consider all the variables at the same time for predicting the quality. In this paper, Taguchi method, regression analysis and neural network were applied to analyze the relationship between processing conditions and solid fraction. A356 alloy was used for the present study, and the learning data were extracted from the reheating experiments. Results by neural network were in good agreement with those by experiment. Polynominal regression analysis was formulated using the test data from neural network. Optimum processing condition was calculated to minimize the grain size and solid fraction standard deviation or to maximize the specimen temperature average. Discussion is given about reheating process of row material and results are presented with regard to accurate process variables fur proper solid fraction, specimen temperature and grain size.