• Title/Summary/Keyword: Physical model

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Reconstruction of structured models using incomplete measured data

  • Yu, Yan;Dong, Bo;Yu, Bo
    • Structural Engineering and Mechanics
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    • v.62 no.3
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    • pp.303-310
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    • 2017
  • The model updating problems, which are to find the optimal approximation to the discrete quadratic model obtained by the finite element method, are critically important to the vibration analysis. In this paper, the structured model updating problem is considered, where the coefficient matrices are required to be symmetric and positive semidefinite, represent the interconnectivity of elements in the physical configuration and minimize the dynamics equations, and furthermore, due to the physical feasibility, the physical parameters should be positive. To the best of our knowledge, the model updating problem involving all these constraints has not been proposed in the existed literature. In this paper, based on the semidefinite programming technique, we design a general-purpose numerical algorithm for solving the structured model updating problems with incomplete measured data and present some numerical results to demonstrate the effectiveness of our method.

A Study on State-Space Model Identification of AC Servo Motor System (AC 서보 전동기 시스템의 상태공간 모델 식별에 관한 연구)

  • 이태훈;김상환;송봉철;원충연;이상석
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2000.11a
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    • pp.199-204
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    • 2000
  • Generally, The systems are so complex that it not possible to obtain reasonable model using physical insight. Also a model based on physical insight contains a number of unknown parameters even if the structure is derived from physical laws. To solve these problems, the systems identification is described in this paper. So, AC servo motor system which has both open loop and closed loop is selected as an example for identification. A state-space model of AC servo motor system is identified through open loop experiment and identified through closed loop experiment and using pole placement integral controller to open loop system. As the results, From ARMA model, We have obtained continuous-time state space model.

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State-Space Model Identification of Arago's Disk System (아라고 원판 시스템의 상태공간 모델 식별)

  • Kang, Ho-Kyun;Choi, Soo-Young;Choi, Goon-Ho;Park, Ki-Heon
    • Proceedings of the KIEE Conference
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    • 2000.07d
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    • pp.2687-2689
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    • 2000
  • In many cases the systems are so complex that it is not possible to obtain reasonable models using physical insight. Also a model based on physical insight contains a number of unknown parameters even if the structure is derived from physical laws. These problems can be solved by system identification. In this paper, Arago's disk system which has both stable and unstable regions is selected as an example for identification and a state-space model is identified using tailor-made model structure of this system. In stable region, a state-space model of Arago's disk system is identified through open loop experiment and a state-space model of unstable region is identified through closed loop experiment after using fuzzy controller to stabilize unstable system.

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Effects of the Variables related to the Health Action Process Approach Model on Physical Activity: A Systematic Literature Review and Meta-analysis (신체활동에 대한 건강행동과정접근모델(Health Action Process Approach Model) 관련 변인의 효과: 체계적 문헌고찰 및 메타분석)

  • Choi, Yun;Yang, Sook Ja;Song, Hye Young
    • Research in Community and Public Health Nursing
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    • v.29 no.3
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    • pp.359-370
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    • 2018
  • Purpose: The purpose of this study is to identify effects of the variables of Health Action Process Approach (HAPA) Model on physical activity. Methods: This study has conducted a systematic literature review and meta-analysis. Sixteen articles were searched through electronic databases (PsycINFO, PubMed, CINAHL, Web of science, Science Direct, RISS, KMBASE, KoreaMed, KISS, DBpia) and additional journals from 2000 to July, 2017. To estimate the effect size (ES), the meta-analysis of the studies was performed by using Comprehensive Meta-Analysis programs. Results: The overall effect size of the variables of HAPA on physical activity was median (ES=.28). Of the core variables of HAPA model, action control (ES=.43) showed the largest effect size, followed by coping self-efficacy (ES=.31) and planning (ES=.31).Additional variables were identified as preparatory behavior (ES=.39) and past physical activity (ES=.24). Through the moderator effect analysis, the effect size was higher in the volitional phase than in the motivational phase, and higher in the healthy group than in the patient group. The higher the proportion of males and the lower the age, the larger the effect size. Conclusion: This finding shows empirical evidence that all core variables of the HAPA model are useful for predicting physical activity. We propose the use of the HAPA model to develop physical activity promotion intervention.

Demonstration of the Usefulness of Optical Coherence Tomography in Imaging a Mouse Tail Model of Lymphedema

  • Kim, Hui Dong;Kim, Dong Kyu;Chae, Yu-Gyeong;Park, Seok Gyo;Kim, Ghi Chan;Jeong, Ho Joong;Sim, Young-Joo;Ahn, Yeh-Chan
    • Current Optics and Photonics
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    • v.1 no.2
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    • pp.132-137
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    • 2017
  • To investigate the usefulness of optical coherence tomography (OCT) for imaging lymphedema, we directly compared it to other histological methods in a mouse model of lymphedema. We performed detailed imaging of the lymphedema lesion on a mouse tail. We imaged the mouse tail in vivo with OCT and created histopathological samples. We constructed a spectrometer-based OCT system using a fiber-optic Michelson interferometer. The light was directed to 50:50 couplers that split the light into reference and sample arms. Backscattered light from a reference mirror and the sample produced an interference fringe. An OCT image of the lymphedema model revealed an inflammatory reaction of the skin that was accompanied by edema, leading to an increase in the light attenuation in the dermal and subcutaneous layers. Similar to OCT image findings, histological biopsy showed an inflammatory response that involved edema, increased neutrophils in epidermis and subdermis, and lymphatic microvascular dilatation. Furthermore, the lymphedema model showed an increase in thickness of the dermis in both diagnostic studies. In the mouse tail model of lymphedema, OCT imaging showed very similar results to other histological examinations. OCT provides a quick and useful diagnostic imaging technique for lymphedema and is a valuable addition or complement to other noninvasive imaging tools.

The Improvement of Forecast Accuracy of the Unified Model at KMA by Using an Optimized Set of Physical Options (기상청 현업 지역통합모델 물리과정 최적화를 통한 예측 성능 향상)

  • Lee, Juwon;Han, Sang-Ok;Chung, Kwan-Young
    • Atmosphere
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    • v.22 no.3
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    • pp.345-356
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    • 2012
  • The UK Met Office Unified Model at the KMA has been operationally utilized as the next generation numerical prediction system since 2010 after it was first introduced in May, 2008. Researches need to be carried out regarding various physical processes inside the model in order to improve the predictability of the newly introduced Unified Model. We first performed a preliminary experiment for the domain ($170{\times}170$, 10 km, 38 layers) smaller than that of the operating system using the version 7.4 of the UM local model to optimize its physical processes. The result showed that about 7~8% of the improvement ratio was found at each stage by integrating four factors (u, v, th, q), and the final improvement ratio was 25%. Verification was carried out for one month of August, 2008 by applying the optimized combination to the domain identical to the operating system, and the result showed that the precipitation verification score (ETS, equitable threat score) was improved by 9%, approximately.

A Study on the RPC Model Generation from the Physical Sensor Model

  • Kim, Hye-Jin;Kim, Dae-Sung;Lee, Jae-Bin;Kim, Yong-Il
    • Korean Journal of Geomatics
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    • v.2 no.2
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    • pp.139-143
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    • 2002
  • The rational polynomial coefficients (RPC) model is a generalized sensor model that is used as an alternative solution for the physical sensor model for IKONOS of the Space Imaging. As the number of sensors increases along with greater complexity, and the standard sensor model is needed, the applicability of the RPC model is increasing. The RPC model has the advantages in being able to substitute for all sensor models, such as the projective, the linear pushbroom and the SAR. This report aimed to generate a RPC model from the physical sensor model of the KOMPSAT-1(Korean Multi-Purpose Satellite) and aerial photography. The KOMPSAT-1 collects 510~730 nm panchromatic imagery with a ground sample distance (GSD) of 6.6 m and a swath width of 17 km by pushbroom scanning. The least square solution was used to estimate the RPC. In addition, data normalization and regularization were applied to improve the accuracy and minimize noise. This study found that the RPC model is suitable for both KOMPSAT-1 and aerial photography.

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Determinant factors of Exercise behaviors in Patients with Arthritis (관절염 환자의 운동행위 결정요인)

  • Suh, Gil-Hee;Lim, Nan-Young
    • Journal of muscle and joint health
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    • v.7 no.1
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    • pp.102-130
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    • 2000
  • The aims of this study were to understand and to predict the determinant factors affecting the exercise behaviors and physical fitness by testing the Ponder's health promotion model, and to help the patients with rheumatoid arthritis and osteoarthritis perform the continuous exercise program, and to help them maximize the physical effect such as muscle strength. endurance, and fuctional status and mental effects including self efficacy and quality of life, and improve the physical and mental wellbeing, and to provide a basis for the nursing intervention strategies. We analyzed the clinical records of 208 patients with rheumatoid arthritis and degenerative arthritis who visited the outpatient clinics at H university hospital in Seoul between October 5, 1999 and October 24, 1999. Data were composed of self reported questionnaire and good of fitness score which were obtained by pedalling the ergometer of bicycle for 9 minutes. SPSS Win 8.0 and Window LISREL 8.12a were used for statistical analysis. 24 Of 54 hypothetical paths were supported in modified model, which was considered as a proper model with improved fit index. The physical fitness was directly influenced by exercise participation behavior and education level, and indirectly by physical fitness, while fatigue, physical disability, pastexercise behavior, life-style, self-efficacy, which explained 20% of physical fitness. The exercise participation were directly influenced by perceived benefits and self-efficacy, and indirectly influenced by life-style, fatigue and physical disability, and directly and indirectly by past exercise behavior, which explained 53% of exercise participation. Exercise score were directly affected by perceived health status, perceived benefits, self efficacy, and past exercise behavior, and were indirectly affected by fatigue, physical disability, and life-style, which explained 50%. Perceived health status were directly influeced by level of education, depression, sleep disorder, and physical disability, which explained 34% of perceived health status. Perceived benefit was directly influenced by fatigue, sleep disorder, physical disability, and life-style, which explained 45%. Perceived barriers was directly influenced by fatigue, sleep disorder, and lifestyle, which explained 9%. Self- efficacy was directly influenced by fatigue, physical disability, past exercise behavior, and level of education, which explained 61%. In conclusion, important variables for physical fitness were exercise participation and level of education, and variables affecting exercise participation were perceived self-efficacy, benefits, and past exercise behavior. Perceived self-efficacy of exercise was a significant predictor of exercise participation. Life-style, fatigue, and physical disability showed direct effects on perceived benefit, perceived barriers, and self-efficacy, and indirect effects on exercise behavior. Therefore, disease related factor should be minimized for physical performance and well being in nursing intervention for patients with rheumatoid arthritis, and plans to promote and continue exercise should be soaked to reduce disability. In addition, Exercise program should be planned and performed by the exact evaluation of exercise according to the ability of the patients and the contents to improve the importance of exercise and self efficacy in self control program, dedicated educational program should be involved.

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Estimation of DAWAST Model Parameters by the Soil Physical characteristics (토양의 물리적 특성을 고려한 DAWAST 모형의 매개변수결정)

  • 박승기;문종필;김태철;안병기;김병규
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1998.10a
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    • pp.8-13
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    • 1998
  • DAWAST model considering the meteorologic and geographic characteristics of the Korean watersheds was newly developed to simulate the daily streamflow. From the condition of soil water storage just before the storm event from DAWAST model, realtime flood can be forecasted by FLOCON model. The purpose of study is that Umax and FC of DAWAST model parameter is obtained by the soil physical characteristics.

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Line Balancing for the Mixed Model Assembly Line Considering Processing Time and Physical Workloads (작업시간과 육체적인 작업부하를 고려한 혼합모델 조립공정의 라인밸런싱)

  • Moon, Sung-Min;Kwon, Keun-Seob;Choi, Gyung-Hyun
    • IE interfaces
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    • v.17 no.3
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    • pp.282-293
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    • 2004
  • Line Balancing is the problem to assign tasks to stations while satisfying some managerial viewpoints. Most researches about the Mixed-Model Line Balancing problems are focused on the minimizing the total processing time or the number of workstations. Independently, some research reports consider the balance issues of the physical workloads on the assembly line. In this paper, we are presenting a new mathematical model to accomplish the line balance considering both the processing time and the workloads at the same time. To this, end, we propose an zero-one integer program problem, and we use the Chebyshev Goal Programming approach as the solution method. Some computational test runs are performed to compare the pay-offs between the processing time and the workloads. And, the test results show us that the reliable balanced work schedules can be obtained through the proposed model.