• Title/Summary/Keyword: curve-fitting

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A Research on the Estimation Method for the SOC of the Lithium Batteries Using AC Impedance (AC 임피던스를 이용한 리튬 전지의 충전상태 추정에 관한 연구)

  • Lee, Jong-Hak;Kim, Sang-Hyun;Kim, Wook;Choi, Woo-Jin
    • The Transactions of the Korean Institute of Power Electronics
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    • v.14 no.6
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    • pp.457-465
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    • 2009
  • Lithium batteries are widely used in mobile electronic devices due to their higher voltage and energy density, lighter weight and longer life cycle compared to other secondary batteries. In particular, high demand for lithium batteries is expected for electric cars. In case of lithium batteries used in electric cars, driving distance must be calculated accurately and discharging should not be done below the level of making it impossible to crank. Therefore, accurate information about state of charge (SOC) becomes an essential element for reliable driving. In this paper, a new method of estimating the SOC of lithium polymer batteries by using AC impedance is proposed. In the proposed method, parameters are extracted by fitting a curve of impedance measured at each frequency on the equivalent impedance model and extracted parameters are used to estimate SOC. Experiments were conducted on lithium polymer batteries with similar capacities made by different manufacturers to prove the validity of the proposed method.

Calculation of Damping Ratio Using Non-Linear Soil Models and Comparison between Measured and Predicted Data (흙의 비선형 모델을 이용한 감쇠비 산정 및 비교)

  • Lee, Hyoung-Kyu;Bae, Yoon-Shin
    • Journal of the Korean Geosynthetics Society
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    • v.10 no.2
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    • pp.21-28
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    • 2011
  • Several theoretical soil nonlinear models to predict damping ratio, which is one of the typical dynamic properties of soils, it is impractical to predict damping ratio. The resonant column and torsional shear test(RC-TS) is used to represent the dynamic behavior of soils from intermediate to medium shear strains. A limitation of RC-TS is measure precise shear strain in large strains and the modified equivalent radius($R_{eq}$) was obtained using both modified hyperbolic model and Ramberg-Osgood model. Bonneville clays were tested using RC-TS test to obtain rotation and torque. The measured rotation and torque were then compared with calculated rotation and torque using curve-fitting method. Then, the nonlinear soil model parameters were obtained and the equivalent radius was calculated using the model parameters.

A Study on Minimal Expression Techniques Depicted in Modern Fashion Design (현대패션에 나타난 최소표현기법에 관한 연구)

  • 김은덕;김민자
    • Journal of the Korean Society of Costume
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    • v.24
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    • pp.157-176
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    • 1995
  • The purpose of this treatise is to study external form and internal meaning of minimal expression fashion which appeared as a major stream in modern fashion trends to understand one aspect of modernism in fashion and also to gain insight into internal value of human beings through fashion. The results can be summarized as follows : Firstly , minimalism is a trend in art attempting to seek essence of the object by presenting simple and disciplined expressions by minimal formative means and minimal production process. Secondly, minimal expression in fashion means seeking simplicity an dpurity by using minimum design elements and minimal productive process. Thirdly, external from of minimal expression fashion can be created through application of following minimal expression techniques. 1. Minimal expression techniques in terms of line mean smooth curve flowing along body contours, straight lines of diagonal lines into desciplined silhouette or rendering internal contour lines. 2. Minimum expression techniques in terms of forms mean forms of smooth curves flowing along boyd or forms with simple geometric forms from qualitative aspects, In terms of volume it means quest for essence of pure body itself by revealing body as it is by minimizing the size of dress or its area and herein is contained using simple geometric pattern or utilizing textiles without any patterns.3. Minimal expression techniques by colors mean simple colors such as primary colors, colors without clear distinctions or natural colors and in terms of quantity it means quest for one color within one item of dress or combination of each items when getting dressed. 4. Minimal expression techniques in terms of fabrics mean fabrics with simple surfaced. In terms of quantity it means quest for essence of tight fitting thin textiles to human body or using transparent materials to human body thus exposing body contours as it is. 5. Minimal expression techniques in terms of productive process mean minimizing process of tailoring , sewing or ornamenting and seeking for simplicity and purity. 6. Minimal expression techniques in terms of manufacturing process mean selection of technique conveying simple image with disciplined simple image. Fourthly, minimal expression fashion with external expression as mentioned in the above lay body-priority style and its internal meaning can be asummed as quest for essence and purity of human body.

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An Experimental Study on the Depth Variation of Water Flow on Steep Open Channel with Constant Width (一定幅 急傾斜 開水路上을 流動하는 물의 깊이 變化에 관한 實驗的 硏究)

  • 박이동
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.10 no.1
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    • pp.86-95
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    • 1986
  • A study on film water flow on steep open channel has been seldom found up to date. Therefore, this paper dealed with the depth variation of film thickness of water (city supply normal water) flowing on steep open channel. For this purpose, Experimental apparatus (made of a normal glass with 160cm of length and 15cm of width) was made and the depths of the water flowing on the channel were measured experimentally, changing the channel slope angle from 30 to 80 degree (5 steps) and the flow rate from 0.25 to 10CPM (11 steps). The results obtained, some characteristics of the film flow on the channel are as follows. (1) When thin film water flowed on steep open channel, the depths of flow tended to increase after decreasing and was kept nearly constant in its downstream in case of laminar and transitional flow region. The turining point of the depths of flow from decrease to increase tended to move downward with the increase of Reynolds number. In turbulent flow region, the depths of flow showed reapid decrease in its upper stream, gradual decrease in its midstream and were kept nearly constant in its downstream. (2) While the differences between the depths of flow along the channel slope got small in its upper stream and got large in its downstream in case of laminar flow region, they got very large in its upper stream and were kept nearly constant in its downstream in case of transitional and turbulent flow region. And the move flow rate increases, the more the differences between the depths of flow along the channel slope got large in its upper stream.

Fitting Cure Rate Model to Breast Cancer Data of Cancer Research Center

  • Baghestani, Ahmad Reza;Zayeri, Farid;Akbari, Mohammad Esmaeil;Shojaee, Leyla;Khadembashi, Naghmeh;Shahmirzalou, Parviz
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.17
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    • pp.7923-7927
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    • 2015
  • Background: The Cox PH model is one of the most significant statistical models in studying survival of patients. But, in the case of patients with long-term survival, it may not be the most appropriate. In such cases, a cure rate model seems more suitable. The purpose of this study was to determine clinical factors associated with cure rate of patients with breast cancer. Materials and Methods: In order to find factors affecting cure rate (response), a non-mixed cure rate model with negative binomial distribution for latent variable was used. Variables selected were recurrence cancer, status for HER2, estrogen receptor (ER) and progesterone receptor (PR), size of tumor, grade of cancer, stage of cancer, type of surgery, age at the diagnosis time and number of removed positive lymph nodes. All analyses were performed using PROC MCMC processes in the SAS 9.2 program. Results: The mean (SD) age of patients was equal to 48.9 (11.1) months. For these patients, 1, 5 and 10-year survival rates were 95, 79 and 50 percent respectively. All of the mentioned variables were effective in cure fraction. Kaplan-Meier curve showed cure model's use competence. Conclusions: Unlike other variables, existence of ER and PR positivity will increase probability of cure in patients. In the present study, Weibull distribution was used for the purpose of analysing survival times. Model fitness with other distributions such as log-N and log-logistic and other distributions for latent variable is recommended.

A Model Approach to Calculate Cancer Prevalence From 5 Year Survival Data for Selected Cancer Sites in India

  • Takiar, Ramnath;Jayant, Kasturi
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.11
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    • pp.6899-6903
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    • 2013
  • Background: Prevalence is a statistic of primary interest in public health. In the absence of good follow-up facilities, it is difficult to assess the complete prevalence of cancer for a given registry area. Objective: An attempt was here made to arrive at complete prevalence including limited duration prevalence with respect to selected sites of cancer for India by fitting appropriate models to 1, 3 and 5 years cancer survival data available for selected population-based registries. Materials and Methods: Survival data, available for the registries of Bhopal, Chennai, Karunagappally, and Mumbai was pooled to generate survival for breast, cervix, ovary, lung, stomach and mouth cancers. With the available data on survival for 1, 3 and 5 years, a model was fitted and the survival curve was extended beyond 5 years (up to 35 years) for each of the selected sites. This helped in generation of survival proportions by single year and thereby survival of cancer cases. With the help of survival proportions available year-wise and the incidence, prevalence figures were arrived for selected cancer sites and for selected periods. Results: The prevalence to incidence ratio (PI ratio) stabilized after a certain duration for all the cancer sites showing that from the knowledge of incidence, the prevalence can be calculated. The stabilized P/I ratios for the cancer sites of breast, cervix, ovary, stomach, lung, mouth and for life time was observed to be 4.90, 5.33, 2.75, 1.40, 1.37, 4.04 and 3.42 respectively. Conclusions: The validity of the model approach to calculate prevalence could be demonstrated with the help of survival data of Barshi registry for cervix cancer, available for the period 1988-2006.

An Efficient Background Modeling and Correction Method for EDXRF Spectra (EDXRF 스펙트럼을 위한 효율적인 배경 모델링과 보정 방법)

  • Park, Dong Sun;Jagadeesan, Sukanya;Jin, Moonyong;Yoon, Sook
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.8
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    • pp.238-244
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    • 2013
  • In energy dispersive X-ray fluorescence analysis, the removal of the continuum on which the X-ray spectrum is superimposed is one of the most important processes, since it has a strong influence on the analysis result. The existing methods which have been used for it usually require tight constraints or prior information on the continuum. In this paper, an efficient background correction method is proposed for Energy Dispersive X-ray fluorescence (EDXRF) spectra. The proposed method has two steps of background modeling and background correction. It is based on the basic concept which differentiates background areas from the peak areas in a spectrum and the SNIP algorithm, one of the popular methods for background removal, is used to enhance the performance. After detecting some points which belong to the background from a spectrum, its background is modeled by a curve fitting method based on them. And then the obtained background model is subtracted from the raw spectrum. The method has been shown to give better results than some of traditional methods, while working under relatively weak constraints or prior information.

Analysis of Experimental Modal Properties of an Electric Cabinet via a Forced Vibration Test Using a Shaker (가진기를 이용한 강제진동시험에 의한 전기 캐비닛의 실험적 모드특성 분석)

  • Cho, Sung-Gook;So, Gi-Hwan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.15 no.6
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    • pp.11-18
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    • 2011
  • Accurate modal identification analysis is required to reasonably perform a seismic qualification of safety-related electric equipment installed in nuclear power plants (NPPs). This study evaluates a variation of the modal properties of an electric equipment cabinet structure in NPPs according to the excitation levels. For the study, an actual electric equipment cabinet was selected as a specimen and was dynamically tested by using a portable exciter in accordance with the level of input vibration energy. Tests were classified into two sets: with-door cases, and without-door cases. Frequency response functions were computed from the signals of the acceleration responses and input motions measured from the vibration tests. A polynomial curve fitting algorithm was used to extract the modal properties from the frequency response functions. This study reviews the variation of the modal properties according to the variation of the excitation levels. The results of the study show that the modal frequencies and the modal dampings of the object specimen varies nonlinearly according to the excitation level of the test motion. Attaching the door increases the modal damping of the cabinet.

Antimicrobial Activity of Florfenicol Against Fish Pathogenic Bacteria and Pharmacokinetics in Blood of Cultured Olive Flounder by Oral Administration (Florfenicol의 어류 병원성 세균에 대한 항균 효과와 경구 투여후 넙치 혈액에서의 약물동태학적 특성)

  • Jung, Sung-Hee;Seo, Jung-Soo
    • Journal of Fisheries and Marine Sciences Education
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    • v.25 no.5
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    • pp.1079-1087
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    • 2013
  • The pharmacokinetics of florfenicol (FF) after oral administration was studied in the cultured olive flounder, Paralichthys olivaceus, using high performance liquid chromatography (HPLC). After single administration of FF (20 mg/kg body weight) by oral route in olive flounder ($700{\pm}50$ g, $23{\pm}1.5^{\circ}C$), the concentration in the serum was determined at 1, 5, 10, 15, 24, 30, 50 and 168 h post-dose. The kinetic profile of absorption, distribution and elimination of FF in serum were analyzed fitting to a two-compartment model by WinNonlin program. The area under the concentration-time curve (AUC), maximum concentration ($C_{max}$), time for maximum concentration ($T_{max}$) and elimination time were 22.51 ${\mu}g{\cdot}h/mL$, 0.84 ${\mu}g/mL$, 8.62 h and 447 h, respectively. The results of this study related to dosage and withdrawal times could be used for prescription of FF in field for the treatment of bacterial diseases in olive flounder.

A Study on the Temperature Characteristics at the Inlet and the Outlet Pipes of a Refrigerator Drain Condenser (냉장고 배출수 응축기 입출구 배관에서의 온도 특성에 관한 연구)

  • Ha, Ji Soo;Kim, Tae Kwon
    • Journal of Energy Engineering
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    • v.23 no.4
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    • pp.247-255
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    • 2014
  • The present study was conducted to elucidate the characteristics of temperature at the inlet and outlet pipes of a refrigerator drain condenser and suggest the method to predict the temperature of the refrigerant at the inlet and outlet pipes of the drain condenser. For this purpose, a built in style refrigerator was installed in a constant temperature chamber to measure temperatures at the inlet and outlet pipes of the drain condenser. From the results of the present analysis, it could be seen that the measured temperatures changed from $37^{\circ}C$ to $46^{\circ}C$ and the actual refrigerant temperatures were higher than the measured temperatures with the difference magnitude of $8^{\circ}C$ to $22^{\circ}C$. The present study suggested that the temperatures of the refrigerator could be calculated with the measured temperatures by introducing curve fitting of the measured temperature. The predicted refrigerant temperatures by the present study had the accuracy within 6% error of the actual refrigerant temperatures.