• Title/Summary/Keyword: Principal component Analysis

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Performance Test of Hypocenter Determination Methods under the Assumption of Inaccurate Velocity Models: A case of surface microseismic monitoring (부정확한 속도 모델을 가정한 진원 결정 방법의 성능평가: 지표면 미소지진 모니터링 사례)

  • Woo, Jeong-Ung;Rhie, Junkee;Kang, Tae-Seob
    • Geophysics and Geophysical Exploration
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    • v.19 no.1
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    • pp.1-10
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    • 2016
  • The hypocenter distribution of microseismic events generated by hydraulic fracturing for shale gas development provides essential information for understanding characteristics of fracture network. In this study, we evaluate how inaccurate velocity models influence the inversion results of two widely used location programs, hypoellipse and hypoDD, which are developed based on an iterative linear inversion. We assume that 98 stations are densely located inside the circle with a radius of 4 km and 5 artificial hypocenter sets (S0 ~ S4) are located from the center of the network to the south with 1 km interval. Each hypocenter set contains 25 events placed on the plane. To quantify accuracies of the inversion results, we defined 6 parameters: difference between average hypocenters of assumed and inverted locations, $d_1$; ratio of assumed and inverted areas estimated by hypocenters, r; difference between dip of the reference plane and the best fitting plane for determined hypocenters, ${\theta}$; difference between strike of the reference plane and the best fitting plane for determined hypocenters, ${\phi}$; root-mean-square distance between hypocenters and the best fitting plane, $d_2$; root-mean-square error in horizontal direction on the best fitting plane, $d_3$. Synthetic travel times are calculated for the reference model having 1D layered structure and the inaccurate velocity model for the inversion is constructed by using normal distribution with standard deviations of 0.1, 0.2, and 0.3 km/s, respectively, with respect to the reference model. The parameters $d_1$, r, ${\theta}$, and $d_2$ show positive correlation with the level of velocity perturbations, but the others are not sensitive to the perturbations except S4, which is located at the outer boundary of the network. In cases of S0, S1, S2, and S3, hypoellipse and hypoDD provide similar results for $d_1$. However, for other parameters, hypoDD shows much better results and errors of locations can be reduced by about several meters regardless of the level of perturbations. In light of the purpose to understand the characteristics of hydraulic fracturing, $1{\sigma}$ error of velocity structure should be under 0.2 km/s in hypoellipse and 0.3 km/s in hypoDD.

Long-term Changes in Soil Chemical Properties in Organic Arable Farming Systems in Korea (작물의 지속적인 유기 재배가 토양의 이화학적 특성변화에 미치는 영향)

  • Lee, Yun-Jeong;Choe, Du-Hoi;Kim, Seung-Hwan;Lee, Sang-Min;Lee, Yong-Hwan;Lee, Byung-Mo;Kim, Tae-Wan
    • Korean Journal of Soil Science and Fertilizer
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    • v.37 no.4
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    • pp.228-234
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    • 2004
  • In organic farming, nutrients for the crop production are mostly supplied by compost containing various organic materials. The long-term organic cultivation would result in continuous changes of soil chemical properties and fertility. The aim of this study was to investigate the contribution of long-term organic cultivation to the soil fertility in Korea focusing on the chemical properties of soil. Soil samples were collected from organic farms that had been cultivated for 8-10 years after certification of organic product through the conversion periods of 2-3 years. Thereby each organic farm had acquired optimal cultivating techniques and soil condition. We separated organic farms into three groups by cultivating crops, i.e. leaf vegetables, fruit vegetables and fruit trees. In each group, five representative farms were chosen in order to investigate the relationships between application rate of compost and nutrient contents in soil. The application rate of compost was approximately $10-15Mg\;10a^{-1}$ for the first 2-3 years at the beginning of organic farming and then reduced to a rate of $3-4Mg\;10a^{-1}$ after stabilization of organic matter content in soil with $30-50g\;10a^{-1}$. However, the continuous organic farming for 8-10 years resulted in accumulation of nutrients, especially of P, in soil probably due to the excessive amounts of compost applied. In conclusion, we suggest that the application rate and organic sources of compost should be decided on the basis of P content in soil by soil testing and thereafter the lack of soil N content for crop cultivation should be compensated by crop rotation with such as legumes. This might be an approach to the original meaning of organic farming as an environmental friendly agriculture.

Geochemistry and Water Quality in the Tidal Flat of Saemangum Area, West Sea of Korea in Summer (하계 새만금 갯벌의 수질 분포 및 지화학적 특성에 관한 연구)

  • Park, Gyung Soo;Park, Soung Yun;Lee, Sam Geun;Lee, Yoon
    • Journal of Wetlands Research
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    • v.6 no.1
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    • pp.133-147
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    • 2004
  • Environmental quality(water and sediment) was analyzed in the tidal flat of Saemangum of Jeonbuk Province, the west coast of Korea, using the 101 sediment samples and 69 water samples collected in September 4~13, 2001. Major water quality parameters with the means of 69 surface water samples are as follows; $25.51{\pm}0.68^{\circ}C$ for water temperature, $29.88{\pm}5.01$ for salinity, $1.40{\pm}0.78mg/L$ for COD, $0.352{\pm}0.417mg/L$ for DIN, and $0.027{\pm}0.023mg/L$ for phosphate, respectively. Higher values were found at the subestuary of Dongjin and Mangyung River, and lower values at the Saemangum embayment and Gomso Bay. There was a significant negative correlation between salinity and the other water quality parameters(p<0.0001) such as COD, nutrients, SS and N/P. This correlation suggested that the major pollution sources be from terrestrial inputs through tributaries in this area. Principal component analysis clearly revealed a spatial variation of water quality; stations with higher values of nutrients and COD located subestuary of tributaries. 14 sediment quality parameters including 8 trace metals were measured using the 101 surface sediment samples. Average values for the parameters are as follows; Al $2.28{\pm}0.92%$, Cd $0.61{\pm}0.27ppm$, Cu $8.95{\pm}4.06ppm$, Fe $1.19{\pm}0.37%$, Mn $182.31{\pm}77.45ppm$, Ni $10.83{\pm}4.97ppm$, Pb $15.20{\pm}4.35ppm$, Zn $41.34{\pm}34.62ppm$, COD $2.68{\pm}1.85mg/g\;dry$, AVS $0.04{\pm}0.08mg/g\;dry$, IL $1.29{\pm}1.08%$, water content $24.11{\pm}4.49%$, TN $0.02{\pm}0.02%$, TC $0.22{\pm}0.30%$. Spatial variations of sediment quality were not clear as water quality. Some higher values were found at the subestuary of Gum River and lower values at the other area. There was a significant positive correlation between the heavy metal concentrations and organic materials within the sediment(p<0.05). Enrichment factors showed the ranges of 1~2 for most of the metals in the sediment except zinc(1~6), indicating no serious exogenous input of heavy metals in the study area. Also, the heavy metal concentrations in the sediment were within the ranges found at the natural marine environments.

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Effect of Socio-demographic Factors on Sensory Properties of Korean Hanwoo Bull Beef by Different Cut and Cooking Methods (사회인구학적 요인이 한우수소고기의 부위 및 요리형태별 관능특성에 미치는 영향)

  • Cho, Soo-Hyun;Kim, Jin-Hyoung;Kim, Jae-Hee;Seong, Pil-Nam;Park, Beom-Young;Kim, Kyung-Eui;Seo, Gu-Reo-Un-Dal-Nim;Lee, Jong-Moon;Kim, Dong-Hun
    • Journal of Animal Science and Technology
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    • v.49 no.6
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    • pp.857-870
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    • 2007
  • This study was conducted to investigate the relationship between the socio-demographic factors and the Korean consumers’ palatability evaluation and to collect the sensory information for development of prediction palatability model of Hanwoo beef. Ten cuts〔Abjin (short plate), Bosup (top sirloin), Cheggt (striploin), Dngsim (loin), Guri (chuck tender), Hongduke (eye of round), Moksim (chuck roll), Sulgit (bottom round), Udoon (top round), Yangi (brisket)〕 were separated from 10 Hanwoo bulls beef(~24 months old) and prepared with the same manner for 3 different cooking methods such as boiling, grilling and roasting. The cooked beef samples were served to 650 consumers recruited from Seoul, Joongbu, Honam and Youngnam locations and evaluated tenderness, juiciness, flavor and overall acceptability. The living location, age, gender, occupation, eating habit and cut were significantly related with the sensory properties when bull beef were cooked as boiled cooking(p<0.05). In grill cooking, only occupation, income and cut had the significant effect on the overall acceptability of Hanwoo bull beef(p<0.01). When bull beef were cooked as Korean traditional roast cooking, consumer’s sensory properties were significantly different by the living location, age, occupation, income, eating habit of consumers and cut(p<0.05). Also, results from the principal component analysis showed that palatability scores of Korean consumers were decided with different contribution scores of tenderness, juiciness, flavor and overall acceptability of cut depending on cooking methods. In conclusion, Korean consumers’ palatability for Hanwoo bull beef were related with the socio-demographic factors and the sensory results were different by cut and cooking methods.

Nutritional Composition and Physico-chemical Meat Quality Properties of Korean Hanwoo Bull Beef (한우수소의 부위별 영양성분조성 및 이화학적 육질특성)

  • Cho, S.H.;Park, B.Y.;Kim, J.H.;Choi, Y.H.;Seong, P.N.;Chung, W.T.;Chung, M.O.;Kim, D.H.;Ahn, C.N.
    • Journal of Animal Science and Technology
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    • v.49 no.6
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    • pp.871-880
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    • 2007
  • This study was conducted to investigate the relationship between the socio-demographic factors and the Korean consumers’ palatability evaluation and to collect the sensory information for development of prediction palatability model of Hanwoo beef. Ten cuts〔Abjin (short plate), Bosup (top sirloin), Cheggt (striploin), Dngsim (loin), Guri (chuck tender), Hongduke (eye of round), Moksim (chuck roll), Sulgit (bottom round), Udoon (top round), Yangi (brisket)〕 were separated from 10 Hanwoo bulls beef(~24 months old) and prepared with the same manner for 3 different cooking methods such as boiling, grilling and roasting. The cooked beef samples were served to 650 consumers recruited from Seoul, Joongbu, Honam and Youngnam locations and evaluated tenderness, juiciness, flavor and overall acceptability. The living location, age, gender, occupation, eating habit and cut were significantly related with the sensory properties when bull beef were cooked as boiled cooking(p<0.05). In grill cooking, only occupation, income and cut had the significant effect on the overall acceptability of Hanwoo bull beef(p<0.01). When bull beef were cooked as Korean traditional roast cooking, consumer’s sensory properties were significantly different by the living location, age, occupation, income, eating habit of consumers and cut(p<0.05). Also, results from the principal component analysis showed that palatability scores of Korean consumers were decided with different contribution scores of tenderness, juiciness, flavor and overall acceptability of cut depending on cooking methods. In conclusion, Korean consumers’ palatability for Hanwoo bull beef were related with the socio-demographic factors and the sensory results were different by cut and cooking methods.

Seasonal Fluctuations of Marine Environment and Phytoplankton Community in the Southern Part of Yeosu, Southern Sea of Korea (여수 남부 협수로 해역의 해양환경과 식물플랑크톤 군집의 계절변동 특성)

  • Noh, Il-Hyeon;Yoon, Yang-Ho;Park, Jong-Sick;Kang, In-Seok;An, Yeong-Kyu;Kim, Seung-Hyun
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.13 no.3
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    • pp.151-164
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    • 2010
  • Field observations on the seasonal variations of environmental factors and phytoplankton community were carried out four times at 30 stations in the narrow strait between Yeosu and Dolsan Island of the Korean South Sea from September 2005 to May 2006. The ranges of water temperature, salinity and extinction coefficient in the surface waters were 5.6~26.3, 25.36~33.92 psu and 0.13~2.13, respectively. The water temperature measured higher at Gamak Bay in summer and spring. It measured higher at Yeosuhae Bay in autumn and winter. Salinity showed uniformity of distributions in almost all areas, except for an area near a sewage disposal outlet. Extinction coefficient indicated that the turbidity of Gamak Bay and the area near the sewage disposal outlet were higher than that of the Yeosuhae Bay. In the phytoplankton community were identified a total of 99 species belonging to 51 genera. The species composition showed itself to be various in summer and autumn, but poor in winter and spring with a high ratio of centric diatoms all the year round. Seasonal succession of dominant species were Skeletonema costatum and Chaetoceros curvisetus in summer, Eucampia zodiacus in autumn and winter, and Chaetoceros affinis and Thalassionema nitzschioides inspring. Standing crops of phytoplankton and Chlorophyll $\alpha$ concentration were greatly higher at Gamak Bay in summer with ranges of $0.2{\times}10^4\;cells\;L^{-1}$ to $296{\times}10^4\;L^{-1}$, and $1.94\;L^{-1}$ to $22.12\;L^{-1}$, respectively. From the results of principal component analysis (PCA), the northern part of Dolsan Island was divided into two or three regions from the characteristics of marine environment and phytoplankton community.

Spatio-temporal Distributions of Organic Matter in Surface Sediment in the Central Part of the South Sea, Korea (남해 중부해역 표층퇴적물 유기물의 시.공간 분포특성)

  • Noh, Il-Hyeon;Yoon, Yang-Ho;Park, Jong-Sick;Soh, Ho-Young;Kim, Dae-Il
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.9 no.4
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    • pp.203-215
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    • 2006
  • Field observations on the spatio-temporal distribution of organic matter of the surface sediment were carried out at 15 stations in the central parts of the South Sea of Korea from April 2002 to January 2003. The range of water temperature and salinity in bottom waters, mud content and water content of surface sediment were $8.06{\sim}23.35^{\circ}C,\;29.20{\sim}34.51\;psu,\;71.2{\sim}99.9%$ and $38.7{\sim}68.9%$, respectively. Measured parameters on the surface sediments of ignition loss (IL), chemical oxygen demand (CODs), phaeopigment, particulate organic carbon (POC) and particulate organic nitrogen (PON) also ranged in $3.9{\sim}l2.5%,\;9.60{\sim}44.05\;mgO_2/g-dry,\;1.58{\sim}29.51\;{\mu}g/g-dry,\;3.12{\sim}13.01\;mgC/g-dry$ and $0.49{\sim}2.00\;mgN/g-dry$, respectively. The spatio-temporal distribution of organic matter demonstrated higher concentrations offshore than at lesions near the coastal line. Higher concentrations occurred in the summer and spring. The results indicated that the origin of organic matter in surface sediments in the central part of the South Sea was autochthonous rather than allocthonous because the organic matter had an average C/N ratio of 6.44 (${\pm}0.51$). However, the composition of autochthonous organic matter was mainly derived from detritus rather than living phytoplankton, which was Indicated by the results of the POC/phaeopigment ratio. A principal component analysis (PCA) indicated that 73.2% of the variability in the data was described by two factors: 1) an 'environmental factor concerning the accumulation of materials (57.3%)' and 2) 'origin of organic matter and the composition by primary production (15.9%)'. The sedimentary environment in the central part of the South Sea was divided into four regions from the factor score of the PCA by the concentrations of organic matter and the composition ratio of organic matters from phytoplankton in surface sediments.

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Effect of seasonal cabbage cultivar (Brassica rapa L. ssp. Pekinesis) on the quality characteristics of salted-Kimchi cabbages during storage period (계절별 배추 품종에 따른 절임배추의 저장중 품질 특성)

  • Choi, Eun Jeong;Jeong, Moon Cheol;Ku, Kyung Hyung
    • Food Science and Preservation
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    • v.22 no.3
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    • pp.303-313
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    • 2015
  • This study investigates the physicochemical, microbiological and sensory characteristics of seasonal salted-Kimchi cabbages to provide basic data on its uniform quality. Generally, seasonal salted-Kimchi samples had different pH values at initial storage periods, but there was no difference in pH between the seasonal samples when stored for longer periods. The samples from the fall and winter seasons were relatively low in acid and high in solid soluble content compared to samples from other seasons. Salted-Kimchi cabbages in the summer showed the highest microbiological number compared to samples from other seasons. In the sensory evaluation, there were differences in the appearance, aroma, and taste, depending on seasonal samples at different storage periods. The correlation coefficient between the quality characteristics in the seasonal samples showed a positive or negative correlation between the quality characteristics at 1% significant level. In the principal component analysis, F1 and F2 were shown the 51.81% and 14.23% of the total variance (66.21%), respectively. In the PCA pattern of seasonal salted-Kimchi cabbages during storage periods, winter samples were distributed on the top of F2, spring samples were in the middle of F2, while the rest of the samples were distributed on the bottom of F2. According to increasing storage periods, initial storage samples were distributed at the left of F1, while other samples were located at the right of F2.

Effects of Pb and CO2 on Soil Microbial Community Associated with Pinus densiflora-Lab (소나무(Pinus densiflora) 생육토양의 미생물 군집에 미치는 납과 CO2의 영향)

  • Hong, Sun-Hwa;Kim, Sung-Hyun;Kang, Ho-Jeong;Ryu, Hee-Wook;Lee, Sang-Don;Lee, In-Sook;Cho, Kyung-Suk
    • Journal of Ecology and Environment
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    • v.29 no.6
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    • pp.551-558
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    • 2006
  • Effects of Pb and $CO_2$ on soil microbial community associated with Pinus densiflora were investigated using community level physiological profiles (CLPP) and 16S rDNA PCR-denaturing gradient gel electrophoresis (DGGE) methods. Two-years pine trees were planted in Pb-contaminated soils and uncontaminated soils, and cultivated for 3 months in the growth chamber where $CO_2$ concentration was controlled at 380 or 760 ppmv. The structure of microbial community was analyzed in 6 kinds of soil samples (CA-0M : $CO_2$ 380 ppmv + Pb 0 mg/kg + initial, CB-0M : $CO_2$ 380 ppmv + Pb 500 mg/kg + initial, CA-3M : $CO_2$ 380 ppmv + Pb 0 mg/kg + after 3 months, CB-3M : $CO_2$ 380 ppmv + Pb 500 mglkg + after 3 months, EA-3M : $CO_2$ 760 ppmv + Pb 0 mg/kg + after 3 months, EB-3M : $CO_2$ 760 ppmv + Pb 500 mg/kg + after 3 months). After 3 months, the substrate utilization in the uncontaminated soil samples (CA-3M vs EA-3M) was not significantly influenced by $CO_2$ concentrations. However, the substrate utilization in the Pb-contaminated soil samples (CB-3M vs EB-3M) was enhanced by the elevated $CO_2$ concentrations. The results of principal component analysis based on substrate utilization activities showed that the structure of microbial community structure in each soil sample was grouped by Pb-contamination. The similarities of DGGE fingerprints were 56.3 % between the uncontaminated soil samples (CA-3M vs EA-3M), and 71.4% between the Pb-contaminated soil samples (CB-3M vs. EB-3M). The similarities between the soil samples under $CO_2$ 380 ppmv (CA-3M vs CB-3M) and $CO_2$, 760 ppmv (EA-3M vs EB-3M) were 53.3% and 35.8%, respectively. These results suggested that the structure of microbial community associated with Pinus densiflora were sensitively specialized by Pb-contamination rather than $CO_2$ concentration.

Object Tracking Based on Exactly Reweighted Online Total-Error-Rate Minimization (정확히 재가중되는 온라인 전체 에러율 최소화 기반의 객체 추적)

  • JANG, Se-In;PARK, Choong-Shik
    • Journal of Intelligence and Information Systems
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    • v.25 no.4
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    • pp.53-65
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    • 2019
  • Object tracking is one of important steps to achieve video-based surveillance systems. Object tracking is considered as an essential task similar to object detection and recognition. In order to perform object tracking, various machine learning methods (e.g., least-squares, perceptron and support vector machine) can be applied for different designs of tracking systems. In general, generative methods (e.g., principal component analysis) were utilized due to its simplicity and effectiveness. However, the generative methods were only focused on modeling the target object. Due to this limitation, discriminative methods (e.g., binary classification) were adopted to distinguish the target object and the background. Among the machine learning methods for binary classification, total error rate minimization can be used as one of successful machine learning methods for binary classification. The total error rate minimization can achieve a global minimum due to a quadratic approximation to a step function while other methods (e.g., support vector machine) seek local minima using nonlinear functions (e.g., hinge loss function). Due to this quadratic approximation, the total error rate minimization could obtain appropriate properties in solving optimization problems for binary classification. However, this total error rate minimization was based on a batch mode setting. The batch mode setting can be limited to several applications under offline learning. Due to limited computing resources, offline learning could not handle large scale data sets. Compared to offline learning, online learning can update its solution without storing all training samples in learning process. Due to increment of large scale data sets, online learning becomes one of essential properties for various applications. Since object tracking needs to handle data samples in real time, online learning based total error rate minimization methods are necessary to efficiently address object tracking problems. Due to the need of the online learning, an online learning based total error rate minimization method was developed. However, an approximately reweighted technique was developed. Although the approximation technique is utilized, this online version of the total error rate minimization could achieve good performances in biometric applications. However, this method is assumed that the total error rate minimization can be asymptotically achieved when only the number of training samples is infinite. Although there is the assumption to achieve the total error rate minimization, the approximation issue can continuously accumulate learning errors according to increment of training samples. Due to this reason, the approximated online learning solution can then lead a wrong solution. The wrong solution can make significant errors when it is applied to surveillance systems. In this paper, we propose an exactly reweighted technique to recursively update the solution of the total error rate minimization in online learning manner. Compared to the approximately reweighted online total error rate minimization, an exactly reweighted online total error rate minimization is achieved. The proposed exact online learning method based on the total error rate minimization is then applied to object tracking problems. In our object tracking system, particle filtering is adopted. In particle filtering, our observation model is consisted of both generative and discriminative methods to leverage the advantages between generative and discriminative properties. In our experiments, our proposed object tracking system achieves promising performances on 8 public video sequences over competing object tracking systems. The paired t-test is also reported to evaluate its quality of the results. Our proposed online learning method can be extended under the deep learning architecture which can cover the shallow and deep networks. Moreover, online learning methods, that need the exact reweighting process, can use our proposed reweighting technique. In addition to object tracking, the proposed online learning method can be easily applied to object detection and recognition. Therefore, our proposed methods can contribute to online learning community and object tracking, detection and recognition communities.