• 제목/요약/키워드: systematic bias

검색결과 658건 처리시간 0.023초

STANDARDISATION OF NIR INSTRUMENTS, INFLUENCE OF THE CALIBRATION METHODS AND THE SIZE OF THE CLONING SET

  • Dardenne, Pierre;Cowe, Ian-A.;Berzaghi, Paolo;Flinn, Peter-C.;Lagerholm, Martin;Shenk, John-S.;Westerhaus, Mark-O.
    • 한국근적외분광분석학회:학술대회논문집
    • /
    • 한국근적외분광분석학회 2001년도 NIR-2001
    • /
    • pp.1121-1121
    • /
    • 2001
  • A previous study (Berzaghi et al., 2001) evaluated the performance of 3 calibration methods, modified partial least squares (MPLS), local PLS (LOCAL) and artificial neural networks (ANN) on the prediction of the chemical composition of forages, using a large NIR database. The study used forage samples (n=25,977) from Australia, Europe (Belgium, Germany, Italy and Sweden) and North America (Canada and U.S.A) with reference values for moisture, crude protein and neutral detergent fibre content. The spectra of the samples were collected using 10 different Foss NIR Systems instruments, only some of which had been standardized to one master instrument. The aim of the present study was to evaluate the behaviour of these different calibration methods when predicting the same samples measured on different instruments. Twenty-two sealed samples of different kind of forages were measured in duplicate on seven instruments (one master and six slaves). Three sets of near infrared spectra (1100 to 2500nm) were created. The first set consisted of the spectra in their original form (unstandardized); the second set was created using a single sample standardization (Clone1); the third was created using a multiple sample procedure (Clone6). WinISI software (Infrasoft International Inc., Port Mathilda, PA, USA) was used to perform both types of standardization, Clone1 is just a photometric offset between a “master” instrument and the “slave” instrument. Clone6 modifies both the X-axis through a wavelength adjustment and the Y-axis through a simple regression wavelength by wavelength. The Clone1 procedure used one sample spectrally close to the centre of the population. The six samples used in Clone 6 were selected to cover the range of spectral variation in the sample set. The remaining fifteen samples were used to evaluate the performances of the different models. The predicted values for dry matter, protein and neutral detergent fibre from the master Instrument were considered as “reference Y values” when computing the statistics RMSEP, SEPC, R, Bias, Slope, mean GH (global Mahalanobis distance) and mean NH (neighbourhood Mahalanobis distance) for the 6 slave instruments. From the results we conclude that i) all the calibration techniques gave satisfactory results after standardization. Without standardization the predicted data from the slaves would have required slope and bias correction to produce acceptable statistics. ii) Standardization reduced the errors for all calibration methods and parameters tested, reducing not only systematic biases but also random errors. iii) Standardization removed slope effects that were significantly different from 1.0 in most of the cases. iv) Clone1 and Clone6 gave similar results except for NDF where Clone6 gave better RMSEP values than Clone1. v) GH and NH were reduced by half even with very large data sets including unstandardized spectra.

  • PDF

자동차디자인에 있어서 여성유저에 관한연구 - 실내편의장치 디자인을 중심으로 - (A study on Female user's in automobiles design -focusing on inter design of automobiles)

  • 박억철;윤명한
    • 디자인학연구
    • /
    • 제19권5호
    • /
    • pp.363-372
    • /
    • 2006
  • 현대는 여성이 소비를 리드하는 시대라고 할 수 있을 만큼 소비시장에서 여성의 파워가 신장되고 있고, 기업들은 기존시장의 과다경쟁과 포화상태에서 벗어나기 위해 여성이라는 소비시장으로 눈을 돌리고 있는 상황이다. 더욱이 소비자 욕구가 다양화되어가는 추세에 부응하기 위해 기업들은 새로운 시장 전략으로써 여성시각에서 상품과 서비스 개발을 적극적으로 전개해야 할 필요성이 커지고 있다. 앞으로 소비시장의 주역으로 주목받고 있는 여성들만의 독특한 문화에 대한 세밀한 관찰과 이해, 조사연구의 필요성이 커지며 지속적으로 수행하는 기업만이 시장선점에 앞장설 수 있을 것이다. 자동차업계도 예외는 아니어서 볼보, 포드자동차를 중심으로 여성전용 자동차 디자인 및 편의장치 개발에 심혈을 기울이고 있으며, 1998년 대우자동차의 '라노스, 줄리엣'을 시작으로 국내에서도 여성자동차 유저를 위한 디자인이 적용되고 있다. 그러나 국내에서는 구체적이고 연구결과가 제시되고 있지는 않은 실정이다. 본 연구는 여성자동차 유저의 중요성을 제기하고, 실내편의장치를 중심으로 여성자동차 유저의 특성 및 니즈를 조사, 분석하여 그 결과를 적용한 디자인을 제안하여 여성구매자들의 중요성을 인식시키는데 목적이 있다.

  • PDF

A Systematic Review of Risk Factors for Brain Metastases and Value of Prophylactic Cranial Irradiation in Non-Small Cell Lung Cancer

  • Sun, Dian-Shui;Hu, Li-Kuan;Cai, Ying;Li, Xiao-Mei;Ye, Lan;Hou, Hua-Ying;Wang, Cui-Hong;Jiang, Yu-Hua
    • Asian Pacific Journal of Cancer Prevention
    • /
    • 제15권3호
    • /
    • pp.1233-1239
    • /
    • 2014
  • Background: The incidence of brain metastases (BM) varies in patients with non-small cell lung cancer (NSCLC), calls into question the value of prophylactic cranial irradiation (PCI). It is possible that clinicopathologic characteristics are associated with the development of BM, but these have yet to be identified in detail. Thus, we conducted the present meta-analysis on risk factors for BM and the value of PCI in patients with NSCLC. Methods: Eligible data were extracted and the risk factors for BM and the value of PCI in patients with NSCLC were analyzed by calculating the pooled odds ratio (OR). Heterogeneity was detected using Q and I-squared statistics, and publication bias was tested by funnel plots and Egger's test. Results: Six randomized controlled trials with a focus on the value of PCI and 13 eligible studies with a focus on risk factors for BM were included. PCI significantly reduced the incidence of BM in patients with NSCLC (p=0.000, pooled OR=0.34, 95% confidence interval = 0.37-0.59). Compared with non-squamous cell carcinoma, squamous cell carcinoma was associated with a low incidence of BM in patients with NSCLC (p=0.000, pooled OR=0.47, 95% confidence interval =0.34-0.65). The funnel plot and Egger's test suggested that there was no publication bias in the current meta-analysis. Conclusions: This meta-analysis provides statistical evidence that compared with non-squamous cell carcinoma, squamous cell carcinoma can be used as a predictor for BM in patients with NSCLC, and PCI might reduce the incidence of BM in patients with NSCLC, but does not provide a survival benefit.

Effectiveness of Education Interventions for the Management of Cancer Pain: A Systematic Review

  • Lee, Yoon Jae;Hyun, Min Kyung;Jung, Yea Ji;Kang, Min Joo;Keam, Bhumsuk;Go, Su Jin
    • Asian Pacific Journal of Cancer Prevention
    • /
    • 제15권12호
    • /
    • pp.4787-4793
    • /
    • 2014
  • Background: Many cancer patients experience poor pain control due to various factors, including misconceptions regarding the use of opioid analgesics. For management of cancer pain, interventions involving education of both patients and physicians have been attempted. Objectives: This review aimed to assess the current evidence of the benefits of education for the management of cancer pain. Methods: We searched the Medline, EMBASE, Cochrane library, and major Korean databases to identify relevant studies. We included most study designs, but excluded case series. The primary outcomes were pain intensity and quality of life (QoL). Two reviewers assessed the risk of bias using the Cochrane's tool for RCT and Risk of Bias Assessment tool for Non-randomized Studies (RoBANS) for non-randomized studies, independently. Results: After extensive searches, 3,324 publications were screened, and 32 studies were selected. The education interventions used in the included studies included a wide variety of education methods, but the most common method was a booklet produced for patients. Regardless of the education method used, the results of the meta-analysis were as follows. The SMDs of the most severe, average, and current pain in the RCTs were significant. The SMD of worst, average, and current pain were -0.34 (-0.55, -0.13), -0.40 (-0.64, -0.15), and -0.79 (-1.35, -0.23). In the non-randomized studies, the effects on average pain were significant, but those on worst and current pain were not. Conclusions: Education intervention reduced the pain of cancer patients. Therefore, patient education could be considered to be an effective method of cancer pain management. However, our data should be interpreted with caution, and studies using standardized protocols are needed to confirm these observations.

VAF 변분법을 이용한 전구 해양자료 동화 연구 (A Study of Global Ocean Data Assimilation using VAF)

  • 안중배;윤용훈;조익현;오혜람
    • 한국해양학회지:바다
    • /
    • 제10권1호
    • /
    • pp.69-78
    • /
    • 2005
  • 본 연구에서는 전구 해양에서 관측되는 ARGO및 TAO해양 자료를 이용하여 해양의 3차원적인 구조를 분석.동화하고 궁극적으로 해양대순환모형을 위한 초기장을 생산하였다. 초기장의 생산을 위하여 전구 해양대순환 모형인 MOM3.1을 이용하였으며 생산한 배경장에, 계산시간과 계산공간을 절약할 수 있는 공간필터를 사용한 변분법(VAF, variational analysis using filter)을 이용하여 ARGO와 TAO 수온 자료를 동화하였다. 또한 본 연구에서는 자료 동화가 미치는 지속적인 영향을 살펴보고자 실험적분을 수행하였는데, 모형의 초기입력 자료를 자료동화 기법을 적용한 경우와 적용하지 않은 두 가지로 나누어 비교 실험을 수행하였다. 본 연구에서 자료 동화된 분석장은 OISST와의 비교를 통해 적절히 생산되었음을 보여주었다. 관측자료를 동화한 분석장을 초기자료로 한 10개월간의 적분결과를 살펴보면, 자료 동화를 통해 제거된 모형의 계통적 bias가 적분이 진행되는 과정에서 관성 중력파 등의 형태로 소멸되지 않고 지속적으로 관측과 유사하게 유지되었다. 이는 본 연구에서 실행한 자료동화가 모형의 역학적인 균형을 유지하면서 적절히 이루어졌음을 의미하며, 전구 대순환 모형을 이용한 중.장기 대기.해양 예측에 이러한 해양 자료동화가 대단히 유용하다는 것을 의미한다.

비정상성을 고려한 원평천 유역의 미래 설계홍수량 산정 (Estimation of Future Design Flood Under Non-Stationarity for Wonpyeongcheon Watershed)

  • 류정훈;강문성;박지훈;전상민;송정헌;김계웅;이경도
    • 한국농공학회논문집
    • /
    • 제57권5호
    • /
    • pp.139-152
    • /
    • 2015
  • Along with climate change, it is reported that the scale and frequency of extreme climate events show unstable tendency of increase. Thus, to comprehend the change characteristics of precipitation data, it is needed to consider non-stationary. The main objectives of this study were to estimate future design floods for Wonpyeongcheon watershed based on RCP (Representative Concentration Pathways) scenario. Wonpyeongcheon located in the Keum River watershed was selected as the study area. Historical precipitation data of the past 35 years (1976~2010) were collected from the Jeonju meteorological station. Future precipitation data based on RCP4.5 were also obtained for the period of 2011~2100. Systematic bias between observed and simulated data were corrected using the quantile mapping (QM) method. The parameters for the bias-correction were estimated by non-parametric method. A non-stationary frequency analysis was conducted with moving average method which derives change characteristics of generalized extreme value (GEV) distribution parameters. Design floods for different durations and frequencies were estimated using rational formula. As the result, the GEV parameters (location and scale) showed an upward tendency indicating the increase of quantity and fluctuation of an extreme precipitation in the future. The probable rainfall and design flood based on non-stationarity showed higher values than those of stationarity assumption by 1.2%~54.9% and 3.6%~54.9%, respectively, thus empathizing the necessity of non-stationary frequency analysis. The study findings are expected to be used as a basis to analyze the impacts of climate change and to reconsider the future design criteria of Wonpyeongcheon watershed.

알레르기성 비염에 대한 한약 및 양약 국소비강외용제의 효과 비교 : 체계적 문헌 고찰 (Comparison of the Effects of Topical Nasal Application on Allergic Rhinitis between Korean and Western Medicine : A Systematic Review of Randomized Controlled Trials)

  • 조효림;오세희;김선혜;성원석;홍승욱;김은정
    • 한방안이비인후피부과학회지
    • /
    • 제32권4호
    • /
    • pp.62-89
    • /
    • 2019
  • Objectives : The purpose of this study is to evaluate the effectiveness and safety of topical nasal application of Herbal medicine compared with Western medicine in the treatment of Allergic Rhinitis(AR). Methods : Electronic databases including Cochrane library, PubMed, EMBASE, CNKI, KMBASE, KISS, NDSL, OASIS, KISS and KJTK(Korean Traditional Knowledge Portal) were searched by the keywords such as 'allergic rhinitis', 'nasal sprays', 'herbal medicine', 'plant extracts', and 'external application'. The quality of each RCTs was assessed by Cochrane Collaboration of 'Risk of bias(RoB) Tool'. Results : 19 RCTs were finally selected from 1419 references screened. 19 RCTs were compared with the effects of topical nasal application of Herbal medicine and Western medicine. Based on the symptom scores from 13 RCTs, topical nasal application of herbal medicine generally has a better effect on relief of AR. The two treatments have similar effects on improving the level of specific factors like IgE, IgG, IL-13, $uLTD_4$ in blood and urine. 8 RCTs showed adverse effects(AEs) in both groups and severe AEs were not reported. Conclusions : This study shows that topical nasal application of herbal medicine can improve symptoms and related factors of allergic rhinitis. Well-designed RCT studies with low risk of bias should be conducted to confirm these findings.

외전신경마비의 한의학 치료에 대한 체계적 문헌 고찰 (Systematic Review of Korean Medicine for the Treatment of Sixth Cranial Nerve Palsy)

  • 원서영;김민지;차지윤;정은선;조현경;유호룡;설인찬;김윤식
    • 대한한방내과학회지
    • /
    • 제40권3호
    • /
    • pp.409-424
    • /
    • 2019
  • Objectives: This research aimed to confirm the efficacy of oriental medicine in sixth cranial nerve palsy and to evaluate the quality of the studies. Methods: Using the medical subject heading (MeSH) keywords "abducens nerve palsy", "abducens nerve paralysis", "sixth nerve palsy", "herbal medicine", "Chinese medicine", "oriental medicine" and "acupuncture", we collected the research papers through an electronic database search in Oriental Medicine Advanced Searching Integrated System (OASIS), National Discovery for Science Leaders (NDSL), PubMed, Cochran Library, and China National Knowledge Infrastructure (CNKI). Results: A total of 136 papers were searched from the databases. Among these, 15 case reports and 8 randomized controlled trials (RCTs) met our criteria. 17 articles were found on the use of acupuncture as the main intervention, 11 on the use of herbal medicine as the main intervention, and 9 on the use of electroacupuncture as the main intervention. The frequently used acupoints were LI4, EX-HN5, GB1, BL2, TE23, LR3, BL1, ST2, GB20, and ST36. All 23 studies confirmed the efficacy of Korean medicine. According to the assessment using the risk of bias, the overall quality of the RCTs was low. Conclusions: Twenty-three papers suggested that Korean medicine treatment for abducens nerve palsy was effective in many cases. Analyzing the potential bias was difficult.

기능성식품으로서 마늘의 혈압 개선 기능성 평가: 마늘건조분말의 준건강인 대상 연구에 대한 메타분석 (Effect of garlic (Allium sativum L.) as a functional food, on blood pressure: a meta-analysis of garlic powder, focused on trials for prehypertensive subjects)

  • 곽진숙;김지연
    • Journal of Nutrition and Health
    • /
    • 제54권5호
    • /
    • pp.459-473
    • /
    • 2021
  • 마늘건조분말을 준건강인이 섭취하였을 때 혈압 개선 효과가 있는지를 평가하기 위하여 메타 분석 기법으로 평가를 수행하였다. 2020년 7월까지 총 3,203건의 자료를 검색하여, 미리 계획한 선정 기준 및 제외 기준에 따라 선별한 결과 총 9건의 연구가 분석에 포함되었다. 편향 위험이 중등도 이상인 2건을 제외하고 총 7건의 연구를 포함하여 분석 결과, 마늘건조분말의 섭취는 수축기혈압 및 이완기혈압을 각각 -6.0 mmHg, -2.7 mmHg 수준으로 대조군 대비 유의하게 개선시키는 것으로 분석되었다.

비만치료에 있어서 환자특성에 따른 인지행동요법과 행동수정요법의 효과 비교: 체계적 문헌고찰 및 메타분석 (Comparison of the Effects of Cognitive Behavioral Therapy and Behavioral Treatment on Obesity Treatment by Patient Subtypes: A Systematic Review and Meta-analysis)

  • 차진영;김서영;신인수;박영배;임영우
    • 한방비만학회지
    • /
    • 제20권2호
    • /
    • pp.178-192
    • /
    • 2020
  • Objectives: The present study aimed to compare the impacts of cognitive behavioral therapy (CBT) and behavioral treatment (BT) on weight loss and psychological outcomes among patients with three different subtypes of obesity: simple obesity, obesity with binge eating disorder, and obesity with depression. Methods: Embase, PubMed, the Cochrane Central Register of Controlled Trials, Research Information Sharing Service, and Korean Studies Information Service System were systematically searched for randomized controlled trials conducted on or before May 2020, that used CBT to treat obesity. Methodological quality was assessed using Cochrane's risk of bias tool 2 and publication bias was evaluated through the funnel plot using the trim and fill method, Egger's test, and Begg and Mazumdar rank correlation test. A meta-analysis was conducted using a random-effects model and the standardized mean difference with 95% confidence interval (CI) was used to determine effect size. Results: Twenty-one randomized controlled trials with a total of 22 intervention arms and 2,590 patients were included. Our study results revealed that the effects of CBT, compared with BT, on weight loss distinctly differed across all patient subgroups. In the simple obesity group, CBT was more effective than BT (Hedges' g=0.138, CI=0.012~0.264); however, in the obesity with binge eating disorder group, BT was more effective than CBT (Hedges' g=-0.228, CI=-0.418~-0.038); in the obesity with depression group, the effect of CBT was not statistically different from that of BT (Hedges' g=0.276, CI=-0.307~0.859). Further studies with larger sample sizes are required to confirm the outcomes observed in this study. Conclusions: Our results indicated that the effects of CBT on obesity treatment vary based on patient subtype. Therefore, our findings suggest that CBT or BT should be selectively recommended as a treatment strategy for different obesity subtypes.