• 제목/요약/키워드: Phases change

검색결과 697건 처리시간 0.027초

Using Classification function to integrate Discriminant Analysis, Logistic Regression and Backpropagation Neural Networks for Interest Rates Forecasting

  • Oh, Kyong-Joo;Ingoo Han
    • 한국지능정보시스템학회:학술대회논문집
    • /
    • 한국지능정보시스템학회 2000년도 추계정기학술대회:지능형기술과 CRM
    • /
    • pp.417-426
    • /
    • 2000
  • This study suggests integrated neural network models for Interest rate forecasting using change-point detection, classifiers, and classification functions based on structural change. The proposed model is composed of three phases with tee-staged learning. The first phase is to detect successive and appropriate structural changes in interest rare dataset. The second phase is to forecast change-point group with classifiers (discriminant analysis, logistic regression, and backpropagation neural networks) and their. combined classification functions. The fecal phase is to forecast the interest rate with backpropagation neural networks. We propose some classification functions to overcome the problems of two-staged learning that cannot measure the performance of the first learning. Subsequently, we compare the structured models with a neural network model alone and, in addition, determine which of classifiers and classification functions can perform better. This article then examines the predictability of the proposed classification functions for interest rate forecasting using structural change.

  • PDF

High School Exploration of a Phase Change Material as a Thermal Energy Storage

  • Ardnaree, Kwanhathai;Triampo, Darapond;Yodyingyong, Supan
    • 대한화학회지
    • /
    • 제65권2호
    • /
    • pp.145-150
    • /
    • 2021
  • The present study describes a hands-on experiment to help students understand the concept of phase change or phase transition and its application in a phase change material (PCM). PCMs are substances that have the capability of storing and releasing large amounts of thermal energy. They act as energy storage materials that provide an effective way to save energy by reducing the electricity required for heating and cooling. Lauric acid (LA) was selected as an example of the PCM. Students investigated the temperature change of LA and the temperature (of air) inside the test tube. The differences in the temperatures of the systems helped students understand how PCMs work. A one-group pretest and posttest design was implemented with 34 grade-11 students in science and mathematics. Students' understanding was assessed using a multiple-choice test and a questionnaire. The findings revealed that the designed activity helped students understand the concept of phase change and its application to materials for thermal energy storage.

정확성 평가결과에 따른 태권도 평원 품새 동작의 운동학적 분석 (Kinematic Analysis of Accuracy Evaluation of Pyeongwon Poomsae)

  • 조용명;류재균;김영숙
    • 한국운동역학회지
    • /
    • 제25권4호
    • /
    • pp.431-440
    • /
    • 2015
  • Objective : The purpose of this study was to investigate the relations between accuracy score and the motions which are performed in PyeongWon Poomsae, thereby developing objectivity in accuracy evaluations for Poomsae competitions. Method : The subjects were six male Poomsae players (age: $21.2{\pm}1.17yrs$, height: $173.4{\pm}3.95cm$, weight: $67.7{\pm}7.65kg$). A three-dimensional motion analysis was performed on the subjects using six high-speed cameras (60 frames/sec) and subjects' performed motions were evaluated by 5 evaluators. The entire Pyeong Poomsae was divided into 13 events and 9 phases; there were three pairs of symmetric phases among them: front kick & turning side kick phases (3PH, 3-1PH), arm motion & stance phases (4PH, 4-1PH), side kick with Hakdari-stance phases (5PH, 5-1PH). Performance time, change and range of COM, height of vertex, and foot of side kicks were analysed. The Data was analysed utilizing correlation analysis. Results : There was a positive correlation between accuracy score and the difference between right and left range of COM (X direction) at 4PH (r=0.921, p=0.009). Conclusion : The results of our study indicate that it is necessary to consider some of objective criterion such as performance time, COM range, and symmetrical movements in accuracy evaluations of Poomsae competitions.

암환자와 가족원의 질병단계에 따른 대처 방법의 비교 (The Comparison of the Coping Patterns of Cancer Patients and Their Caregivers According to the Phases of Illness)

  • 양영희
    • 대한간호학회지
    • /
    • 제28권4호
    • /
    • pp.970-979
    • /
    • 1998
  • Cancer has been considered a life-threatening disease and coping patterns could have a strong impact the physical and psychological health of patients and their family. The purpose of this study was to identify the change of coping patterns according to the phases of illness in the patients with cancer and their family caregivers and to compare the coping patterns of patients with those of their caregivers. The phases of illness consisted of 1st(initial) stage, 2nd(metastatic or recurred) stage and 3rd (terminal) stage based on literature. The coping methods were measured using the modified Ways of Coping Questionnaire by Lazarus & Folkman(1984). Seventy-nine patients(35 in stage 1, 31 in stage 2, and 13 in stage 3) and ninety-two caregivers (38 in stage 1, 30 in stage 2 and 24) agreed to participate from two general hospitals in Seoul and Choongnam. No significant changes were found in the coping patterns according to the phases of illness in both groups. Patients in stage 2 and caregivers in stages 2 and 3 problem-focused coping methods were significantly used more than emotion-focused coping methods. Patients in stage 1 significantly used two coping strategies that were cognitive reconstruction and emotion expression more than caregivers. Patients in stage 2 significantly used emotion-focused coping methods including minimizing threat, blame, and emotion expression excepting wishful thinking more than caregivers. We need more research to identify the relationship between the coping methods and their efficiencies through longterm observation and attempt to develope the nursing interventions that could have an improvement on positive coping methods and provide guidance on the problems the patients experience.

  • PDF

영주저반의 관입상과 화성과정 (Intrusive Phases and Igneous Pricesses in the Yeongju Batholith)

  • 황상구
    • 자원환경지질
    • /
    • 제32권6호
    • /
    • pp.669-688
    • /
    • 1999
  • The Yeongju granitoid batholith is a plutonic complex of huge area (1180km2) intruding the metamorphic rocks of the Yeongnam massif. The batholith, which is divided into fivelithofacies, consists of three separate plutons. The oldest Buseok pluton comprises four lithofacies: hornblende biotite tonalite, porphyrotoc biotite granodiorite, equigranular biotite grandiorite and biotite granite. The middle Chunyang pluton has been called as Chunyang granite that ranges in compostion from granodiorite to granite. The youngest Jangsu pluton is intrusions that has lithofacies of two mica granite. The contact between Buseok pluton and the rest two plutons shows obvious intrusive relations, but relation between the Chunyang and the Jangsu pluton is far away, so gives no indication of relative ages. Changes in nextures and micristructures, as well as in the mineral contents, take place between rock types og the plutons. only the Buseok pluton shows faliations of two type: magmatic foliation and regional mylonal foliation. K-Ar age deteminations fall into 171.7$\pm$3.2~162.3$\pm$3.1 Ma in the Buseok pluton, 153.9$\pm$2.9 Ma in the Chunyang pluton and 145.3$\pm$2.7 Ma in the jangsu Pluton. The batholith presents three separate intrusive phases which range in composition from tonalite to granite to granite. Each intrusive phase apperars to have been intruded in a pulse from an underlying, differentiating magma. The petrochemical data showthat three plutons are within the diagnostic range for continental arc orogenic tectonic setting, whereas Jangsu pluton approaches postorogenic setting. The data suggest that three plutons are calc-aclkalline series, and that temporal compositional variations change progerssively from tonalite through grandiorite to granite between the intrusive phases. so we consider that the magmas for all the phases were probably derived from a differentiation by fractional crystallization of a parental magma. The tonalite magma of the Buseok phase was tapped was tapped from a chamber deep in the crust, and then would have to rise at a rapid rate to its final level of emplacement. The tonalite magma in the chamber was gradually enolved through granodiorite magma into granite magma by fractional crystallization. The magmas of the younger phases were respectively tapped with temporal interval from a evolved magma of the chamber that rose into a shallower lever in the crust, and rose to their present level of emplacement.

  • PDF

여자 고등학생들의 월경주기에 따른 스트레스인자 지각 및 정신병리 (Perceived Stressor and Psychopathology during the Menstrual Cycle in High School Girls)

  • 고경봉;현태영;구민성
    • 정신신체의학
    • /
    • 제7권2호
    • /
    • pp.233-240
    • /
    • 1999
  • 본 연구는 청소년 여성에서 월경전기, 월경기, 월경후기간 스트레스인자 지각 및 정신병리를 비교하기 위해 시행되었다. 여자 고등학생 341명(인문계 164명, 예능계 177명)을 대상으로 하였고, 평가도구는 스트레스인자 지각 및 정신병리를 평가하기 위해 global assessment of recent stress(GARS) scale과 symptom checklist-90-revised(SCL-90R)를 이용하였다. 월경기보다 월경전기 및 월경후기 중에 관계의 변화에 관련된 스트레스인자 지각점수가 각각 유의하게 더 높았다. 그러나 세 기간 중 정신병리는 유의한 차이를 보이지 않았다. 한편 인문계 학생들이 예능계 학생들보다 일상생활의 변화유무에 관한 스트레스인자 지각점수는 물론 강박증 척도접수와 positive symptom total(PST) 점수가 유의하게 더 높았다. 결론적으로 일부 스트레스인자지각이 월경기보다 월경전기 및 월경후기 중에 더 현저할 가능성이 높으나 정신병리는 월경주기와 관계가 없는 것으로 나타났다. 이 결과는 청소년 여성들의 정신병리가 월경주기 이외의 다른 변수들의 영향을 받을 가능성이 있음을 시사하였다.

  • PDF

슈퍼 듀플렉스 다층용접부의 미세조직 및 공식(Pitting Corrosion)에 미치는 용접열사이클의 영향 (Effect of Welding Thermal Cycle on Microstructure and Pitting Corrosion Property of Multi-pass Weldment of Super-duplex Stainless Steel)

  • 남성길;박세진;나혜성;강정윤
    • 대한용접접합학회:학술대회논문집
    • /
    • 대한용접접합학회 2009년 추계학술발표대회
    • /
    • pp.37-37
    • /
    • 2009
  • Due to their high corrosion resistance and improved mechanical properties super-duplex stainless steel (SDSS) are extensively used in petrochemical plants such as facilities in modern oil platform and off-shore process equipment. It is well known that the best mechanical and corrosion resistance properties of super-duplex stainless steel are obtained with a microstructure having approximately equal amounts of austenite and ferrite. And it is also known that sigma($\sigma$), chi($\chi$), secondary austenite(${\gamma}2$), chromium carbides and nitride affected adversely their properties. Therefore these phases must be avoided. However, effects of succeeding weld thermal cycle on the change of microstructure of weldment at multi-pass weld were not seldom experimentally researched. Therefore in the present work, the change of weldmetal microstructure and the effect of microstructure on pitting corrosion property at $40^{\circ}C$ by succeeding each weld thermal cycle were researched. The thermal history of root side was measured experimentally and the change of microstructure of root weld according to thermal cycle of each weld layer was evaluated. And the relationship between microstructure of root weld and pitting corrosion property at $40^{\circ}C$ was also investigated. Results of the present work are show as below. 1. The ferrite contents of root weld are gradually reduced by succeeding weld thermal cycle. 2. The 2nd phases such as sigma($\sigma$), chi($\chi$), secondary austenite(${\gamma}2$), chromium carbides and nitride are increased gradually by succeeding weld thermal cycle. 3. The pitting corrosion was detected in root weld part and weight loss by pitting corrosion is increased in proportional to the time exposed over $600^{\circ}C$ of the root weld. 4. The succeeding weld thermal cycles affect the microstructure of the former weldments and promote the formation of 2nd phases. That is, the more succeeding welds are added, the more 2nd phases are gradually increased. Consequently, it is thougth that this adversely affects pitting corrosion property.

  • PDF

Using Structural Changes to support the Neural Networks based on Data Mining Classifiers: Application to the U.S. Treasury bill rates

  • 오경주
    • 한국데이터정보과학회:학술대회논문집
    • /
    • 한국데이터정보과학회 2003년도 추계학술대회
    • /
    • pp.57-72
    • /
    • 2003
  • This article provides integrated neural network models for the interest rate forecasting using change-point detection. The model is composed of three phases. The first phase is to detect successive structural changes in interest rate dataset. The second phase is to forecast change-point group with data mining classifiers. The final phase is to forecast the interest rate with BPN. Based on this structure, we propose three integrated neural network models in terms of data mining classifier: (1) multivariate discriminant analysis (MDA)-supported neural network model, (2) case based reasoning (CBR)-supported neural network model and (3) backpropagation neural networks (BPN)-supported neural network model. Subsequently, we compare these models with a neural network model alone and, in addition, determine which of three classifiers (MDA, CBR and BPN) can perform better. For interest rate forecasting, this study then examines the predictability of integrated neural network models to represent the structural change.

  • PDF

황화물계 3가 크롬도금욕에서 크롬-탄소 및 크롬-탄소-인 합금도금의 전착과 결정화거동 (Electro-deposition and Crystallization Behaviors of Cr-C and Cr-C-P Alloy Deposits Prepared by Trivalent Chromium Sulfate Bath)

  • 김만;김대영;박상언;권식철;최용
    • 한국표면공학회지
    • /
    • 제37권2호
    • /
    • pp.80-85
    • /
    • 2004
  • Chromium-carbon (Cr-C) and chromium-carbon-phosphorus (Cr-C-P) alloy deposits using trivalent chromium sulfate baths containing potassium formate were prepared to study their current efficiency, hardness change and phase transformations behavior with heat treatment, respectively. The current efficiencies of Cr-C and Cr-C-P alloy deposits increase with increasing current density in the range of 15-35 A/dm$^2$. Carbon content of Cr-C and phosphorous of Cr-C-P layers decreases with increasing current density, whereas, the carbon content of Cr-C-P layer is almost constant with the current density. Cr-C deposit shows crystallization at $400^{\circ}C$ and has (Cr+Cr$_{ 23}$$C_{6}$) phases at $800^{\circ}C$. Cr-C-P deposit shows crystallization at $600^{\circ}C$ and has (Cr+Cr$_{23}$ $C_{6}$$+Cr_3$P) phases at $800^{\circ}C$. The hardness of Cr-C and Cr-C-P deposits after heating treatment for one hour increase up to Hv 1640 and Hv 1540 and decrease about Hv 820 and Hv 1270 with increasing annealing temperature in the range of $400~^{\circ}C$, respectively. The hardness change with annealing is due to the order of occurring of chromium crystallization, precipitation hardening effect, softening and grain growth with temperature. Less decrease of hardness of Cr-C-P deposit after annealing above $700^{\circ}C$ is related to continuous precipitation of $Cr_{23}$ $C_{6}$ and $Cr_3$P phases which retard grain growth at the temperature.