• Title/Summary/Keyword: separation index

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A Comparison of Three Low Back Disability Questionnaires With Rasch Analysis (라쉬분석을 이용한 세 가지 요통 장애 설문지의 비교)

  • Kim, Gyoung-Mo;Park, So-Yeon;Yi, Chung-Hwi
    • Physical Therapy Korea
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    • v.18 no.3
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    • pp.94-102
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    • 2011
  • The purpose of this study was to review existing assessment tools for patients with low back pain and improve them through combination. A total of 314 patients with low back pain participated. Their condition was assessed using the Oswestry Disability Questionnaire (ODQ), the Quebec Back Pain Disability Scale (QBPD), and the Back Pain Functional Scale (BPFS). Rasch analysis was applied to identify inappropriate items, item difficulties, and the separation index. In this study, the 'sex life' item of the ODQ (10 items) and the 'sleeping' item of the BPFS (12 items) showed misfit statistics, whereas all items of the QBPD (20 items) were appropriate. After combining the ODQ, QBPD and BPFS, Rasch analysis was applied. The 'pain intensity', and the 'sex life' item of the ODQ and the 'throw a ball' item of QBPD showed misfit statistics. These 3 items were retained for further analysis. The remaining 42 combined ODQ-QBPD-BPFS items were arranged according to difficulty. For all subjects, the most difficult item was 'pain intensity', whereas the easiest was 'take food out of the refrigerator'. As the separation index of 42 combined ODQ-QBPD-BPFS was higher than that of the three questionnaires separately, difficulty of items varied with some need for rearrangement. The results of this study confirmed the possibility and need for a new back pain disability assessment tool, and produced one. Further study is needed to refine the questionnaire in consideration of psychosocial and occupational factors.

Clinical and Radiologic Analysis of Posterior Apophyseal Ring Separation Associated with Lumbar Disc Herniation

  • Bae, Jung-Sik;Rhee, Woo-Tack;Kim, Woo-Jae;Ha, Seong-Il;Lim, Jae-Hyeon;Jang, Il-Tae
    • Journal of Korean Neurosurgical Society
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    • v.53 no.3
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    • pp.145-149
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    • 2013
  • Objective : We analyzed the clinical and radiologic features of posterior apophyseal ring separation (PARS) with lumbar disc herniation and suggest the proper management options according to the PARS characteristics. Methods : We reviewed case series of patients with PARS who underwent surgery of lumbar disc herniation. Preoperative symptoms, neurologic status, Body Mass Index, preoperative and postoperative Visual Analogue Scale (VAS) and Korean-Oswestry Disability Index (K-ODI) scores, operation types were obtained. PARS size, locations, the degree of resection were assessed. Results : PARS was diagnosed in 109 (7.5%) patients among 1448 patients given surgical treatment for single level lumbar disc herniation. There were 55 (50.5%) small PARS and 54 (49.5%) large PARS. Among the large PARS group, 15 (27.8%) had lower endplate PARS of upper vertebra at the level of disc herniation. Thirty-nine (72.2%) were upper endplate PARS of lower vertebra. Among the group with upper endplate PARS of lower vertebra, unresected PARS was diagnosed in 12 (30.8%) cases and resected PARS was diagnosed in 27 (69.2%) cases. VAS and K-ODI scores changes were $3.6{\pm}2.9$ and $5.4{\pm}6.4$ in the unresected PARS group, $5.8{\pm}2.1$ and $11.3{\pm}7.1$ in the resected PARS group. The group with upper endplate PARS of lower vertebra showed significant difference of VAS (p=0.01) and K-ODI (p=0.013) score changes between unresected and resected PARS groups. Conclusion : The large PARS of upper endplate in lower vertebra should be removed during the surgery of lumbar disc herniation. High level or bilateral side of PARS should be widely decompressed and arthrodesis procedures are necessary if there is a possibility of secondary instability.

Multiple Stellar Populations of Galactic Globular Clusters NGC 6656 and NGC 6723

  • Chun, Sang-Hyun;Sohn, Young-Jong;Lee, Young-Wook;Han, Sang-Il;Roh, Dong-Goo;Lee, Jae-Woo
    • The Bulletin of The Korean Astronomical Society
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    • v.36 no.2
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    • pp.143.1-143.1
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    • 2011
  • Deep Ca,b,y images obtained from the CTIO 4m Blaco telescope are used to investigate the multiple stellar populations of red giant branch (RGB) and sub-giant branch (SGB) in Galactic globular clusters NGC 6656 and NGC 6723. For NGC 6656, confirming the result of Lee et al. (2009), we find two discrete populations of the RGB stars of which mean color separation is about 0.2 mag in hk[=(Ca-b)-(b-y)] index. Furthermore, we also find the bimodel distribution of the SGB stars in (hk, y) color-magnitude diagram. A new finding is that the (hk, y) color-magnitude diagram of NGC 6723 shows two distinct RGB stars with different calcium abundances of which mean color separation is about 0.12 mag in hk index. This multiple stellar feature has not been observed in previous observation, suggesting that NGC 6723 may also be a possible relic of dwarf galaxies that merged into the Milky Way in the past. Thus our result adds further constraints to the merging scenario of the Galaxy formation. Unfortunately, the split of SGB stars in NGC 6723 is not obvious. We will present some statistical results to compare properties of two populations in two clusters.

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THE EFFECTS OF DIETARY CONSISTENCY ON THE TRABECULAR BONE ARCHITECTURE IN GROWING MOUSE MANDIBULAR CONDYLE : A STUDY USING MICRO-CONFUTED TOMOGRAPHY (성장 중인 쥐에서 음식물의 경도가 하악 과두의 해면골에 미치는 영향 : 미세전산화 단층촬영을 이용한 연구)

  • Youn, Seok-Hee;Lee, Sang-Dae;Kim, Jung-Wook;Lee, Sang-Hoon;Hahn, Se-Hyun;Kim, Chong-Chul
    • Journal of the korean academy of Pediatric Dentistry
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    • v.31 no.2
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    • pp.228-235
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    • 2004
  • The development and proliferation of the mandibular condyle can be altered by changes in the biomechanical environment of the temporomandibular joint. The biomechanical loads were varied by feeding diets of different consistencies. The purpose of the present study was to determine whether changes of masticatory forces by feeding a soft diet can alter the trabecular bone morphology of the growing mouse mandibular condyle, by means of micro-computed tomography. Thirty-six female, 21 days old, C57BL/6 mice were randomly divided into two groups. Mice in the hard-diet control group were fed standard hard rodent pellets for 8 weeks. The soft-diet group mice were given soft ground diets for 8 weeks and their lower incisors were shortened by cutting with a wire cutter twice a week to reduce incision. After 8 weeks all animals were killed after they were weighed. Following sacrifice, the right mandibular condyle was removed. High spatial resolution tomography was done with a Skyscan Micro-CT 1072. Cross-sections were scanned and three-dimensional images were reconstructed from 2D sections. Morphometric and nonmetric parameters such as bone volume(BV), bone surface(BS), total volume(TV), bone volume fraction(BV/TV), surface to volume ratio(BS/BV), trabecular thickness(Tb. Th.), structure model index(SMI) and degree of anisotropy(DA) were directly determined by means of the software package at the micro-CT system. From directly determined indices the trabecular number(Tb. N.) and trabecular separation(Tb. Sp.) were calculated according to parallel plate model of Parfitt et al.. After micro-tomographic imaging, the samples were decalcified, dehydrated, embedded and sectioned for histological observation. The results were as follow: 1. The bone volume fraction, trabecular thickness(Tb. Th.) and trabecular number(Tb. N.) were significantly decreased in the soft-diet group compared with that of the control group (p<0.05). 2. The trabecular separation(Tb. Sp.) was significantly increased in the soft-diet group(p<0.05). 3. There was no significant differences in the surface to volume ratio(BS/BV), structure model index(SMI) and degree of anisotropy(DA) between the soft-diet group and hard-diet control group (p>0.05). 4. Histological sections showed that the thickness of the proliferative layer and total cartilage thickness were significantly reduced in the soft-diet group.

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A Study on Relationship between Streamflow Variability and Baseflow Contribution in Nakdong River Basin (낙동강 수계에서의 하천유량 변동성과 기저유출 기여도의 관계 분석)

  • Han, Jeong Ho;Lim, Kyoung Jae;Jung, Younghun
    • Journal of The Korean Society of Agricultural Engineers
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    • v.58 no.1
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    • pp.27-38
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    • 2016
  • More severe and frequent flood and drought have increased the attentions on the river management. In particular, baseflow is an important element among many streamflow characteristics because streamflow is mainly consisted of direct runoff and baseflow. In this regard, this study attempted to analyze the relationship between streamflow variability and baseflow contributions on Nakdong river basin. For this, two Streamflow Variability Indices (SVI) were used: Coefficient of Variation (CV) and Coefficient of Flow Regime (CFR). Furthermore, baselow separation was individually conducted by three methods (PART, WHAT and BFLOW), and based on this, Baseflow Index (BFI) was calculated. Also, we used the daily streamflow data retrieved from 27 gauge stations in Nakdong river basin for baseflow separation. The results showed that BFI calculated by three models ranges from 0.14 to 0.90 for 27 gauge stations. For SVI, BFI has much higher correlation with CV than with CFR. Also, the inversely proportional relationship between BFI and CV showed that higher baseflow contribution, less streamflow variability.

A Study on Type Analysis and the Formative Exaggeration Phenomenon in Fashion through Indexical Consideration of Delong's Theory: Focus on 16th to 20th Century Women's Costumes (Delong의 지표적 고찰에 따른 형태적 과장 현상과 유형 분석 연구: 근세.근대 복식을 중심으로)

  • Bae, Jung-Min
    • Journal of the Korean Home Economics Association
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    • v.48 no.6
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    • pp.9-16
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    • 2010
  • The formative exaggeration phenomenon, which makes the plastic space, escaping from the form peculiar to the human body, is being developed into the more diversified and abstract structure. This study analyzed the form and shape of costumes with objective attitude through the use of an oppositional concept method, which Delong presented from the formative viewpoint. Delong's theory, which was presented in this study, can be said to be one index that analyzed the form and shape of costumes. The costumes of the Renaissance Era, in which formative exaggeration is remarkable, are determinate in that they are closed and static, and can be classified into part, planer separation, and flat. The costumes of the Baroque and Rococo Eras are divided into similar formative perspectives, and can be said to be open, whole, and integrated due to indeterminate and diverse decorations. Entering modern times, the formative-exaggeration phenomenon in costumes of the Romantic Era are characterized by closed, part, and planer separation similar to costumes of the Renaissance Era. However, in the aspect of sleeve design and decoration, the characteristics of determinate and indeterminate were considered.

A Hybrid CBPWM Scheme for Single-Phase Three-Level Converters

  • Wang, Shunliang;Song, Wensheng;Feng, Xiaoyun;Ding, Rongjun
    • Journal of Power Electronics
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    • v.16 no.2
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    • pp.480-489
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    • 2016
  • A novel hybrid carrier-based pulse width modulation (CBPWM) scheme that combines unipolar and dipolar modulations is proposed for single-phase three-level rectifiers, which are widely applied in railway traction drive systems. The proposed CBPWM method can satisfy the volt-second balancing principle in the complete modulation index region through overmodulation compensation. The modulation scheme features two modulation modes: unipolar and dipolar. The operation range limits of these modulation modes can be modified by changing the separation coefficient. In comparison with the traditional unipolar CBPWM, the proposed hybrid CBPWM scheme can provide advantageous features, such as lower high-order harmonic distortion of the line current and better utilization of switching frequency. The separation coefficient value is optimized to achieve the maximum utilization of these advantages. The experimental results verify the feasibility and effectiveness of the proposed hybrid CBPWM scheme.

Incremental Fuzzy Clustering Based on a Fuzzy Scatter Matrix

  • Liu, Yongli;Wang, Hengda;Duan, Tianyi;Chen, Jingli;Chao, Hao
    • Journal of Information Processing Systems
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    • v.15 no.2
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    • pp.359-373
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    • 2019
  • For clustering large-scale data, which cannot be loaded into memory entirely, incremental clustering algorithms are very popular. Usually, these algorithms only concern the within-cluster compactness and ignore the between-cluster separation. In this paper, we propose two incremental fuzzy compactness and separation (FCS) clustering algorithms, Single-Pass FCS (SPFCS) and Online FCS (OFCS), based on a fuzzy scatter matrix. Firstly, we introduce two incremental clustering methods called single-pass and online fuzzy C-means algorithms. Then, we combine these two methods separately with the weighted fuzzy C-means algorithm, so that they can be applied to the FCS algorithm. Afterwards, we optimize the within-cluster matrix and betweencluster matrix simultaneously to obtain the minimum within-cluster distance and maximum between-cluster distance. Finally, large-scale datasets can be well clustered within limited memory. We implemented experiments on some artificial datasets and real datasets separately. And experimental results show that, compared with SPFCM and OFCM, our SPFCS and OFCS are more robust to the value of fuzzy index m and noise.

Effects of Aerobic Granular Sludge Separator on the Stability of Aerobic Granular Sludge (AGS) (호기성 그래뉼 슬러지 선별 분리기가 호기성 그래뉼 슬러지의 안정성에 미치는 영향)

  • Kwon, Gyutae;Kim, Hyun-Gu;Ahn, Dae-Hee
    • Journal of Environmental Science International
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    • v.30 no.12
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    • pp.1081-1092
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    • 2021
  • In this study, the effect on the stability of Aerobic Granular Sludge (AGS) caused by an AGS separator was investigated. The AGS separator was a hydrocyclone. The main factors of the AGS separator were filter pore size (0.125~0.600 mm), conical-to-cylindrical ratio (1.5~3.0), and operating time (1~20 min). The AGS/mixed liquor suspended solid (MLSS) ratio gradually increased to 0.500 mm (AGS/MLSS: 84.3±3.0%). AGS was best separated at the conical-to-cylindrical ratio of 2.5 (AGS/MLSS: 84.7±3.3%). As the operating time increased, the AGS separation performance also tended to increase. The shortest AGS separator run time, but the highest AGS separation performance was 10 min (87.0±2.5%). AGS stability was evaluated by operating the selected AGS separator and sequencing batch reactor. The average removal efficiencies of TOC, TCODCr, SS, TN, and TP were 95.7%, 96.9%, 93.0%, 89.0%, and 96.2%, respectively, which met the effluent standards in Korea. In addition, the AGS/MLSS ratio tended to remain constant, and the sludge volume index demonstrated a tendency to decrease from 140 mL/g to 70 mL/g. During the operation, the particles of AGS in optical microscope observations gradually increased.

Hydrograph Separation using Geochemical tracers by Three-Component Mixing Model for the Coniferous Forested Catchment in Gwangneung Gyeonggido, Republic of Korea

  • Kim, Kyongha;Yoo, Jae-Yun
    • Journal of Korean Society of Forest Science
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    • v.96 no.5
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    • pp.561-566
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    • 2007
  • This study was conducted to clarify runoff production processes in forested catchment through hydrograph separation using three-component mixing model based on the End Member Mixing Analysis (EMMA) model. The study area is located in the coniferous-forested experimental catchment, Gwangneung Gyeonggido near Seoul, Korea (N 37 45', E 127 09'). This catchment is covered by Pinus Korainensis and Abies holophylla planted at stocking rate of 3,000 trees $ha^{-1}$ in 1976. Thinning and pruning were carried out two times in the spring of 1996 and 2004 respectively. We monitored 8 successive events during the periods from June 15 to September 15, 2005. Throughfall, soil water and groundwater were sampled by the bulk sampler. Stream water was sampled every 2-hour through ISCO automatic sampler for 48 hours. The geochemical tracers were determined in the result of principal components analysis. The concentrations of $SO_4{^{2-}$ and $Na^+$ for stream water almost were distributed within the bivariate plot of the end members; throughfall, soil water and groundwater. Average contributions of throughfall, soil water and groundwater on producing stream flow for 8 events were 17%, 25% and 58% respectively. The amount of antecedent precipitation (AAP) plays an important role in determining which end members prevail during the event. It was found that ground water contributed more to produce storm runoff in the event of a small AAP compared with the event of a large AAP. On the other hand, rain water showed opposite tendency to ground water. Rain water in storm runoff may be produced by saturation overland flow occurring in the areas where soil moisture content is near saturation. AAP controls the producing mechanism for storm runoff whether surface or subsurface flow prevails.