• Title/Summary/Keyword: Selection-bias

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Music for Pediatric Patients in Medical Settings: A Systematic Review of Randomized Controlled Trials (소아환자를 위한 음악: 무작위 임상연구의 체계적인 문헌고찰)

  • Lee, Jin Hyung
    • Journal of Music and Human Behavior
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    • v.10 no.2
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    • pp.1-33
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    • 2013
  • The aim of this study was to systematically review the latest clinical trials in music medicine and medical music therapy for pediatric patients. Thirteen databases were searched to obtain randomized controlled/crossover design studies published between the year 2000 and 2012 in English language. Out of 1012 articles retrieved in the initial search, fifteen studies were identified based on an exclusion criteria. Overall, selected articles involved children 1 month to 18 years, sample size of 11 to 150, and total participants of 987. Studies were classified and compared as music medicine or music therapy studies through a systematic synthesis assessing general characteristics, methodological quality, measured outcomes, types of interventions and the study results. Seven music medicine and eight music therapy studies measured seven dependent variables using thirty-six different measurement tools with a large heterogeneity in the selection, type, and method of music interventions. Evaluation of the methodological quality revealed that many studies did not provide a full report of the research method, and did not meet some or most methodological standards, such as randomization, allocation concealment, double or partial blinding, and intention to treat analysis. Although overall research results were positive if not significant, poor methodological quality and heterogeneity in design and intervention strategies raise the question of research bias and trustworthiness issues. The systematic review concluded that music may have a valuable clinical effect in addressing the physical and psychosocial needs of hospitalized children, although more rigorous, homogeneous and replicable studies are greatly needed.

Research Activity Assessment with the Use of Scientometrics: OLED Case Analysis (과학계량학을 이용한 연구활동 평가 : OLED 사례 분석)

  • Yeo, Woon-Dong;Lee, Woo-Hyoung;Lee, Sang-Pil
    • Journal of Korea Technology Innovation Society
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    • v.10 no.2
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    • pp.230-254
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    • 2007
  • Scientometrics means the metrics of science, and it plays a role in the measurement of scientists' activities by using research results like papers. Objective numerical values or indicators obtained by scientometric analysis may make a significant contribution to correct evaluation by excluding political or relationship bias or revealing significant researchers or their research fields that have been assessed relatively lower for their performance. In the period when the scale of technology was relatively large, such as for the development of heavy chemistry, it was possible to make a not-bad selection by an assessment made only with the intuition of the assessor. However, it is nearly impossible for experts with a narrow knowledge in a field to judge the direction of change correctly as the current science technology changes rapidly and tremendously. Even in an assessment of research performance of researchers or research institutions, only some notable researchers are able to attract attention owing to the Metthew effect, and the majority who have accumulated research results in depth are not able to receive reasonable research funding. Therefore, it might be natural that there is a growing need for assessment using scientometrics. The purpose of this research is to suggest some applicable scientometric techniques for an assessment of research performance to science and technology researchers and policy planners. In order to accomplish this, we used a frequency analysis of papers and its citations to assess the research performance of researchers, institutions, and countries for OLED technology as a case study. Furthermore, we position detailed technologies for OLED technology as arriving, growing, maturing, and declining technology by utilizing several network analysis techniques, make groups with researchers and institutions of same research interest. And we review the current international joint research of Korea, China, and Japan, who are in a competitive relationship. Also, at the end of each analysis result, we describe what kind of assessment should be available to Korean policy planners and research managers for such scientometric analysis results.

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A Performance Analysis by Adjusting Learning Methods in Stock Price Prediction Model Using LSTM (LSTM을 이용한 주가예측 모델의 학습방법에 따른 성능분석)

  • Jung, Jongjin;Kim, Jiyeon
    • Journal of Digital Convergence
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    • v.18 no.11
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    • pp.259-266
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    • 2020
  • Many developments have been steadily carried out by researchers with applying knowledge-based expert system or machine learning algorithms to the financial field. In particular, it is now common to perform knowledge based system trading in using stock prices. Recently, deep learning technologies have been applied to real fields of stock trading marketplace as GPU performance and large scaled data have been supported enough. Especially, LSTM has been tried to apply to stock price prediction because of its compatibility for time series data. In this paper, we implement stock price prediction using LSTM. In modeling of LSTM, we propose a fitness combination of model parameters and activation functions for best performance. Specifically, we propose suitable selection methods of initializers of weights and bias, regularizers to avoid over-fitting, activation functions and optimization methods. We also compare model performances according to the different selections of the above important modeling considering factors on the real-world stock price data of global major companies. Finally, our experimental work brings a fitness method of applying LSTM model to stock price prediction.

Exploring the Difficulties of High School Students in Self-Directed Scientific Inquiry (고등학생의 자기 주도적 과학탐구연구에서 나타난 어려움 탐색)

  • Kim, Gahyoung;Ha, Minsu
    • Journal of The Korean Association For Science Education
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    • v.39 no.6
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    • pp.707-715
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    • 2019
  • The self-directed inquiry to improve students' core scientific competency is an important teaching method. Students experience a variety of difficulties in carrying out their inquiry tasks, sometimes fail to produce the desired results, or fail to perform a meaningless inquiry. This study was conducted to identify the causes of difficulties and failures in students' self-directed scientific inquiry. The study involved 16 high school students with experience in science research at science high schools and science-focused high schools. The data collection consisted of in-depth interviews centered on semi-structured open questions. Qualitative data analysis was imputed by finding paragraphs from the interview material that might reveal the difficulties and failures experienced by participants and the reasons for them. The study found that most of the causes of failure were lack of ability, incomplete procedures, and selection of complicated tasks. A variety of cognitive biases, such as overconfidence, planning fallacy, and groupthink, were also analyzed as causes. Based on the results of the study, it is necessary to develop an educational strategy that students can be fully prepared to reduce their trials and errors in a self-directed inquiry maximally.

Characteristics of InGaAs/GaAs/AlGaAs Double Barrier Quantum Well Infrared Photodetectors

  • Park, Min-Su;Kim, Ho-Seong;Yang, Hyeon-Deok;Song, Jin-Dong;Kim, Sang-Hyeok;Yun, Ye-Seul;Choe, Won-Jun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.324-325
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    • 2014
  • Quantum wells infrared photodetectors (QWIPs) have been used to detect infrared radiations through the principle based on the localized stated in quantum wells (QWs) [1]. The mature III-V compound semiconductor technology used to fabricate these devices results in much lower costs, larger array sizes, higher pixel operability, and better uniformity than those achievable with competing technologies such as HgCdTe. Especially, GaAs/AlGaAs QWIPs have been extensively used for large focal plane arrays (FPAs) of infrared imaging system. However, the research efforts for increasing sensitivity and operating temperature of the QWIPs still have pursued. The modification of heterostructures [2] and the various fabrications for preventing polarization selection rule [3] were suggested. In order to enhance optical performances of the QWIPs, double barrier quantum well (DBQW) structures will be introduced as the absorption layers for the suggested QWIPs. The DBWQ structure is an adequate solution for photodetectors working in the mid-wavelength infrared (MWIR) region and broadens the responsivity spectrum [4]. In this study, InGaAs/GaAs/AlGaAs double barrier quantum well infrared photodetectors (DB-QWIPs) are successfully fabricated and characterized. The heterostructures of the InGaAs/GaAs/AlGaAs DB-QWIPs are grown by molecular beam epitaxy (MBE) system. Photoluminescence (PL) spectroscopy is used to examine the heterostructures of the InGaAs/GaAs/AlGaAs DB-QWIP. The mesa-type DB-QWIPs (Area : $2mm{\times}2mm$) are fabricated by conventional optical lithography and wet etching process and Ni/Ge/Au ohmic contacts were evaporated onto the top and bottom layers. The dark current are measured at different temperatures and the temperature and applied bias dependence of the intersubband photocurrents are studied by using Fourier transform infrared spectrometer (FTIR) system equipped with cryostat. The photovoltaic behavior of the DB-QWIPs can be observed up to 120 K due to the generated built-in electric field caused from the asymmetric heterostructures of the DB-QWIPs. The fabricated DB-QWIPs exhibit spectral photoresponses at wavelengths range from 3 to $7{\mu}m$. Grating structure formed on the window surface of the DB-QWIP will induce the enhancement of optical responses.

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Study of requirements and conditions to be improved for voluntary occupational health program in worksite (자율 산업보건사업 실시를 위한 전제조건과 개선되어야 할 사항의 중요도에 관한 연구)

  • Song, Jae-Seok;Won, Jong-Uk;Son, Myong-Sei;Cha, Bong-Suk;Roh, Jae-Hoon
    • Journal of Preventive Medicine and Public Health
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    • v.30 no.4 s.59
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    • pp.840-851
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    • 1997
  • To perform voluntary occupational health program in worksites, regulational supports are necessary. The regulational supports include assessment of current occupational health program and appropriate incentives. The purpose of this study is to find out the requirements of voluntary occupational health program and conditions to be improved. Study population was industrial health managers of both industries with less than 300 workers and over 300 workers, and the member of labor union who is responsible for safety and health in worksite. Two different questionnaire were used to find out the requirements and conditions to be improved respectively, The results were; 1. The category which prevalence rate of occupational injuries and occupational disease should be lower than national average was most important in health managers employed in industries over 300 workers and followed by reporting system, education, worksite policy, work environment assessment, protective equipment, consequently. But those employed in industries less than 300 workers showed high importance in prevalence rate of occupational injuries and disease, reporting system, worksite policy, work environment assessment, protective equipment, education, consequently 2. The members of labor union thought that worksite policy was most important and the next is education, reporting system, work environment assessment, protective equipment, prevalence rate of occupational injuries and disease. 3. There were difference in importance of education and worksite policy according to the size of industries. Reporting system, prevalence rate of occupational injuries and disease, and worksite policy had different importance between members of labor union and health managers. 4. In the results of quiestionnaire for conditions to be improved, the most important condition was top manager's willingness except personal protective equipments, and followed by financial support, legal support. The limitations of this study were the problems of representativeness of study population. but voluntary health program should be performed in worksites which have relatively good occupational health system. So, this selection bias could not disrupt our results.

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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.

Comparative Study on the Impact Factors in Job Stress in Occupational Therapists Working in Korean: A Systematic Review and Meta-Analysis (국내 작업치료사의 직무스트레스 요인 비교 연구: 체계적 고찰과 메타분석)

  • Cha, Yu-Jin
    • The Journal of the Korea Contents Association
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    • v.12 no.6
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    • pp.380-389
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    • 2012
  • In this study, Systematic review and meta-analysis using the correlation coefficients was carried out to integrate precedent studies on factors affecting domestic occupational therapists' job stress. It aims at providing basic information resources of preventing and reducing stress of occupational therapists and effective counter-measurement to improve quality of occupational therapy and to establish efficient human resource management policy. Systematic review and meta-analysis were performed on eight thesis proven relevant to selection criteria in order to figure out correlation coefficients value by total, and factors correlation coefficients value. Also homogeneity test and publication bias test was performed too. The total correlation coefficients value of occupational therapists was .30 which was statistically significant. As to job stress factors, the organization related factor showed the highest correlation of coefficiency, followed by factors other than the organization related, physical environment, job related factor and personal factor. This research result can be used as a reference to prevent and reduce job stress of occupational therapists and to develop an effective measurement scheme.

A Quantitative Study on How the Cheonghae Anti-piracy Unit influences the Occurrence of Maritime Piracy near Somalia (청해부대 파병(다국적 해군의 대(對)해적 작전)이 소말리아 인근 해적사건 발생에 미치는 영향에 관한 정량적연구)

  • Han, Jong-Hwan
    • Strategy21
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    • s.46
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    • pp.123-157
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    • 2020
  • This research focuses on one important type of non-traditional threat, maritime piracy, and tries to supplement previous research from the perspective of military power, especially naval power. When considering the elements of military power, naval power is a core independent variable to explain piracy incidents. Indeed, naval power can play a key role in solving piracy problems, since naval power is the only legitimate force to respond to piracy in the sea. It is natural that well equipped and trained naval power in the sea increases the probability of capturing pirates, which leads to increasing the costs of piracy and decreasing its occurrences. In addition, since naval combatant ships have more impressive weapons than those of pirate boats, just the presence of naval combatant ships could serve to deter piracy incidents in the sea. The main purpose of this research is finding the effectiveness of large multinational naval efforts to deter piracy incidents in Africa. With this research purpose, I analyze 771 piracy incidents that occurred in African states from 2009 to 2014. Furthermore, I include all 33 coastal states in Africa regardless of the experiences of piracy incidents in order to avoid selection bias, which is very common in quantitative-based piracy incidents research. The dependent variable of this research is frequency of maritime piracy incidents for a country-year and the independent variable is the number of multi-national naval warships that operate near Somalia. With this analysis, I find the large number of multi-state naval combatant ships are negatively related to piracy incidents. In other words, as a main means to counteract piracy incidents, multi-state naval combatant ships are conducive to reduce piracy incidents near Somalia, since it increases costs (being captured) of conducting piracy.

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.