• Title/Summary/Keyword: Data Bias

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The Study on the Mapping of Wind Resource using Moving Filter Technique at Udo, Jeju Island (무빙필터 기법을 적용한 제주 우도지역의 풍력자원지도 작성에 대한 연구)

  • Moon, Seo Jeong;Ko, Jung Woo;Lee, Byung Gul
    • Journal of Korean Society for Geospatial Information Science
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    • v.20 no.4
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    • pp.29-36
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    • 2012
  • In order to create a wind resource map, we need wind data, contour map and roughness map. Moving Filter technique was applied to Udo of Jeju Island to improve the accuracy and efficiency of creating roughness map based on the Land Cover Map of the Ministry of Environment. The Land Cover Map was simplified using moving filtering, and the roughness map was created with this Land Cover Map. The wind resource map was created using this roughness map. Finally, we verified the validity and application of moving filter technique for wind resource map. As a result, the wind map which was created using the roughness map with moving filtering showed bias values which were all negative. It means the wind map is underestimated to values of wind energy and RMSE values were also from 0.0237m/s to 0.0253m/s at 50m height. In other words, estimation of wind resource using image filtering provides reliable results at 80m height typically when the wind turbine is installed. Finally, we found that image filtering technique is very useful tool to make wind resource map.

Effect of Acupuncture on Sciatica in Rat Models: Systematic Review and Meta-analysis (좌골신경통 백서모델에서 침치료의 효과: 체계적 문헌고찰 및 메타분석)

  • Yoon, Ye-Ji;Kim, Soojeon;Cho, Jae-Heung;Kim, Koh-Woon;Song, Mi-Yeon
    • Journal of Korean Medicine Rehabilitation
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    • v.30 no.1
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    • pp.79-93
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    • 2020
  • Objectives While sciatic neuropathy is one of the common symptoms which have the lifetime incidence of 13~40%, still there is no consensus about the standardized and the most effective conservative treatment. In addition, the importance of systematic review and meta-analysis of preclinical are growing as they could suggest possible effective treatment strategy for future studies. Therefore, we conducted systematic review and meta-analysis to estimate analgesic effect of acupuncture on sciatica in rat models. Methods Systematic search was conducted for all controlled comparative preclinical trials which assessed analgesic effect of acupuncture in sciatica rat models. Database of PubMed, EMBASE, Web of Science, CNKI and 6 Korean databases were used. The primary outcome was pain, which is evaluated by stimulus behavior tests in rat models. We assessed the methodological quality with Systematic Review Centre for Laboratory Animal Experimentation's risk of bias tool. RevMan 5.3 was used for meta-analysis and subgroup analysis was conducted according to treatment site, acupuncture point, treatment period and frequency used in electroacupuncture. Results 14 studies were finally included following our inclusion criteria. The data from meta-analysis indicated that the acupuncture significantly improved the result values of behavior tests for pain evaluation, compared to no-treatment control group in animal models (standardized mean difference=4.43, 95% confidence interval 3.16 to 5.69, Z=6.84, p<0.00001; χ2=68.02, p<0.00001; I2=82%). The results of subgroup analysis indicate that acupuncture treatment of unilateral site, distal acupoints, longer treatment period and applying 2/100 Hz frequency in electroacupuncture could be more effective. Conclusions Systematic review and meta-analysis of animal studies are getting important for the future clinical studies and the improvement of heatlh care. Therefore the results of the study would provide evidence and better design for the forthcoming studies.

Dry Etching of PMMA and Polycarbonate in a Diffusion Pump-based Capacitively Coupled O2 Plasma (확산펌프 기반의 O2 축전결합 플라즈마를 이용한 PMMA와 폴리카보네이트의 건식 식각)

  • Park, Ju-Hong;Lee, Seong-Hyun;Choi, Jyoung-Hoon;Noh, Ho-Sub;Lee, Je-Won
    • Korean Journal of Materials Research
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    • v.19 no.8
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    • pp.421-426
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    • 2009
  • We report on the capacitively coupled O2 plasma etching of PMMA and polycarbonate (PC) with a diffusion pump. Plasma process variables were process pressure and CCP power at 5 sccm $O_2$ gas flow rate. Characterization was done in order to analyze etch rate, etch selectivity, surface roughness, and morphology using stylus surface profilometry and scanning electron microscopy. Self bias decreased with increase of process pressure in the range of 25$\sim$180 mTorr. We found an important result for optimum pressure for the highest etch rate of PMMA and PC, which was 60 mTorr. PMMA and PC had etch rates of 0.46 and 0.28 ${\mu}m$/min under pressure conditions, respectively. More specifically, etch rates of the materials increased when the pressure changed from 25 mTorr to 60 mTorr. However, they reduced when the pressure increased further after 60 mTorr. RMS roughnesses of the etched surfaces were in the range of 2.2$\sim$2.9 nm. Etch selectivity of PMMA to a photoresist was $\sim$1.5:1 and that of PC was $\sim$0.9:1. Etch rate constant was about 0.04 ${\mu}m$/minW and 0.02 ${\mu}m$/minW for PMMA and PC, respectively, with the CCP power change at 5 sccm $O_2$ and 40 mTorr process pressure. PC had more erosion on the etched sidewall than PMMA did. The OES data showed that the intensity of the oxygen atomic peak (777.196 nm) proportionally increased with the CCP power.

Patient's Perception for Developing Research Questions of a Clinical Practice Guideline of Korean Medicine for Degenerative Lumbar Spinal Stenosis: A Descriptive Cross-Sectional Survey (퇴행성 요추 척추관 협착증의 한의표준임상진료지침 핵심질문 설정에 대한 환자 인식 설문 조사: 단면 설문 연구)

  • Choi, Seo Young;Bae, Ji Min;Choi, Ji Won;Yang, Gi Young;Lee, Byung Ryul;Kim, Kun Hyung
    • Korean Journal of Acupuncture
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    • v.35 no.3
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    • pp.130-138
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    • 2018
  • Objectives : The purpose of this study is to explore patients' perceptions that deserve attention when designing core questions for a clinical practice guideline of Korean medicine(KM) for degenerative lumbar spinal stenosis (LSS). Methods : Patients who had been admitted to Pusan National Korean Medicine Hospital from November 1, 2015 to October 31, 2016 were invited to the survey. Patients were eligible if they were both clinically and radiologically confirmed as degenerative LSS. The structured questionnaire was distributed by mail and outpatient visits. Questions included types of experienced Korean/Western medical interventions for LSS, their perceived effectiveness on symptoms, the necessity for studies of KM for degenerative LSS, the types of KM interventions to be investigated and the types of outcome measures after treatments. Data were descriptively analysed. Results : Twenty of thirty-one invited participants responded to the questionnaire. Acupuncture and herbal medicine were the most frequently used KM interventions. Eighteen respondents reported that KM treatments were helpful for their improvement. Sixteen patients who mentioned that research on KM is needed chose acupuncture as the top priority(88%) among KM interventions. The most important outcomes in the view of nineteen respondents included functional recovery (68%) and pain relief (53%). Thirteen respondents (65%) replied that both short-term and long-term outcome were important for them. Conclusions : Our findings may have limited validity due to the small number of respondents and the potential selection and information bias. Further qualitative studies and large-scale surveys to comprehensively identify patients' views are warranted.

A Study on the Improvement Plan of Green Belt Community Support Program (개발제한구역 주민지원제도 개선방향에 관한 연구)

  • Lee, Mi-Hong;Yoon, Jeong-Joong;Yoon, In-Sook
    • Land and Housing Review
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    • v.4 no.4
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    • pp.317-332
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    • 2013
  • The purpose of this study is to survey the community support program of Green Belt from 2001 to 2011 and propose the improvement of the institution. For research method, the projects were analyzed by year, area, and category using statistical data. The improvement of the institution was drawn through the opinion survey of the interest group such as residents and public servants. For 10 years, 2007 community support projects were carried out and the total amount of government expenditure was 583.9 billion won. Among the support items, life convenience projects comprise 96.7%. For area, metropolitan area comprise 32.5%. There is a bias in items and areas. According to the survey of the residents and public servants, the satisfaction for the community support program is increasing. But it is necessary to enlarge the direct life cost support, activate community involvement and develop new project type. Proposed new projects are such as making characteristic village for income creation, planning for the landscape preservation using historic and traditional resources, making leisure space for nearby residents, and projects for the aged people. And it is proposed to give incentive to the characteristic village projects through competition.

Comparison of Expression Profiling of Gastric Cancer by O1igonucleotide and cDNA Microarrays (O1igonucleotide Microarray와 cDNA Microarray를 이용한 위암조직의 대단위 유전자 발현 비교)

  • Jung, Kwang-Hwa;Kim, Jung-Kyu;Noh, Ji-Heon;Eun, Jung-Woo;Bae, Hyun-Jin;Lee, Sug-Hyung;Park, Won-Sang;Yoo, Nam-Jin;Lee, Jung-Young;Nam, Suk-Woo
    • YAKHAK HOEJI
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    • v.51 no.3
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    • pp.179-185
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    • 2007
  • Gastric cancer is one of the most common malignancies in Korea, but the predominant molecular event underlying gastric carcinogenesis remain unknown. Recently, DNA microarray technology has enabled the comprehensive analysis of gene expression level, and as such has yielded great insight into the molecular nature of cancer, However, despite the powerful approach of this techniques, the technical artifacts and/or bias in applied array platform limited the liability of resultant tens of thousand data points from microarray experiments. Therefore, we applied two different any platforms, such as olignucleotide microarray and cDNA microarray, to identify gastric cancer related large-scale molecular signature of the same human specimens. When thirty sets of matched human gastric cancer and normal tissues subjected to oligonucleotide microarray, total 623 genes were resulted as differently expressed genes in gastric cancer compared to normal tissues, and 252 genes for cDNA microarray analysis. In addition, forty three outlier genes which reflect the characteristic expression signature of gastric cancer beyond array platform and analytical protocol was recapitulated from two different expression profile. In conclusion, we were able to identify robust large-scale molecular changes in gastric cancer by applying two different platform of DNA microarray, this may facilitate to understand molecular carcinogenesis of gastric cancer.

A Study on Analysis of R&D Intensity based on Patent Citation Information: Case Study on Self-driving Car of Google (특허인용정보 기반의 연구집중도 분석에 관한 연구: 구글의 자율주행자동차 기술 중심으로)

  • Lee, Junseok;Kim, Jongchan;Lee, Joonhyuck;Park, Sangsung;Jang, Dongsik
    • Journal of the Korean Institute of Intelligent Systems
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    • v.26 no.4
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    • pp.327-333
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    • 2016
  • An autonomous vehicle is a convergence of artificial intelligence and a vehicle which can drive itself while analyzing the real-time situation on a road without a driver. A lot of research achievements have been revealed through the media and Google is considered to be the best leading company in this field. The use of patent information which contains various information such as bibliographic data and information about technologies is a good way to find out the R&D direction of a company and develop a reasonable strategy. This study is aimed at investigating the direction to which Google focuses its R&D capabilities and establishing strategies for technology development. Google's patents about autonomous vehicles were collected and the degree of research bias was analyzed using Social Network Analysis based on citations indicating the quality of a patent. Based on the results, the strategies for technology development was eventually proposed. As a result, it was revealed that Google focused its R&D capabilities on the part of hardware control to make up for its lack of hardware-oriented technologies. As of now, Google obtained remarkable achievements, so it seems reasonable that last-movers consider cooperative research with Google.

The Interpretation of Different Recreation Benefits According to Time Horizon in the Contingent Valuation Method (가상가치평가법(假想價値評價法)에서 시간범위(時間範圍)에 따른 휴양가치(休養價値)의 차이(差異) 해석(解析))

  • Kim, Joon-Soon
    • Journal of Korean Society of Forest Science
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    • v.88 no.1
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    • pp.117-123
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    • 1999
  • Consumer surplus is to be a value concerning a time horizon. Especially it is very important how long time horizon would be chosen in contingent market. This study aimed to provide causes of difference recreation benefits through discount rate in many aspects. The data were collected by personal interviews with visitors in Songnisan National Park. The respondents answered yes or no, dichotomous choice, on recreation benefits according to a chosen time horizon, one year or five years. The probit model was used in the analysis. In order to avoid the truncation bias of upper bound, the median was chosen as the recreation benefits of visitor. As the result, the value was evaluated to be 16,569 Won for one year and 27,111 Won for five years. The discount rate is estimated 153% annually to coincide different recreation benefits. The reasons of the high discount rate were to be interpreted as following five types : (1)uncertainty of future consumption (2)increasing of probability of the substitution owing to increasing of time horizon (3)recognization of different time horizons (4) effect by the price ratio of goods and utility function (5) overestimation of the recreation benefits owing to a basic premium of payment vehicle.

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A study on Ability and Utilization of Smart Devices for the Disabled: Focusing on the Effect of Education for Smart Device Utilization (장애인의 스마트기기 사용능력 및 활용도에 관한 연구 - 스마트기기 활용교육의 효과를 중심으로 -)

  • Song, Jihyang;Kim, Dongwook
    • Informatization Policy
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    • v.21 no.2
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    • pp.67-88
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    • 2014
  • The research hypothesis of this paper is that education for smart device utilization has a positive effect on ability and utilization of smart devices for the disabled. The data for disabled of NIA's 2012 survey about digital divide is used, and the research method is "Heckman's 2-stage method" which considers the problem of selection bias. As a research result, this paper says that the disabled who had experience of education for smart device utilization have higher level of ability and utilization of smart devices. Also, a high level of education and family income, professional career and young generation have been very positive effect on the high level of ability and utilization of the disabled. The level of ability and utilization of the blind tend to be lower than those of the physically disabled. These results remind that the education for smart device utilization for the disabled is important and effective. And various contents and methods of education which are appropriate for the disability types should be developed.

Development and assessment of framework for selecting multi-GCMs considering Asia monsoon characteristics (아시아 몬순특성을 고려한 다중 GCMs 선정방법 개발 및 평가)

  • Kim, Jeong-Bae;Kim, Jin-Hoon;Bae, Deg-Hyo
    • Journal of Korea Water Resources Association
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    • v.53 no.9
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    • pp.647-660
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    • 2020
  • The objectives of this study are to develop a framework for selecting multi-GCMs considering Asia monsoon characteristics and assess it's applicability. 12 climate variables related to monsoon climates are selected for GCM selection. The framework for selecting multi-GCMs includes the evaluation matrix of GCM performance based on their capability to simulate historical climate features. The climatological patterns of 12 variables derived from individual GCM over the summer monsoon season during the past period (1976-2005) and they are compared against observations to evaluate GCM performance. For objective evaluation, a rigorous scoring rule is implemented by comparing the GCM performance based on the results of statistics between historical simulation derived from individual GCM and observations. Finally, appropriate 5 GCMs (NorESM1-M, bcc-csm1-m, CNRM-CM5, CMCC-CMS, and CanESM2) are selected in consideration of the ranking of GCM and precipitation performance of each GCM. The selected 5 GCMs are compared with the historical observations in terms of monsoon season and monthly mean to validate their applicability. The 5 GCMs well capture the observational climate characteristics of Asia for the 12 climate variables also they reduce the bias between the entire GCM simulations and the observational data. This study demonstrates that it is necessary to consider various climate variables for GCM selection and, the method introduced in this study can be used to select more reliable climate change scenarios for climate change assessment in the Asia region.