• Title/Summary/Keyword: Selection Bias

Search Result 337, Processing Time 0.026 seconds

A Tunable Band-Pass Filter for Multi Bio-Signal Detection (대역폭 조정 가능한 다중 생체 신호 처리용 대역 통과 필터 설계)

  • Jeong, Byeong-Ho;Lim, Shin-Il;Woo, Deok-Ha
    • Journal of IKEEE
    • /
    • v.15 no.1
    • /
    • pp.57-63
    • /
    • 2011
  • This paper presents a tunable band pass filter (BPF) for multi bio-signal detection. The bandwidth can be controlled by the bias current of transconductance (gm), while conventional BPF exploited switchable capacitor array for band selection. With this design technique, the die area of proposed BPF reduced to at least one tenth the area of conventional design. The simulation results show the high cut-off frequency tuning range of from 100Hz to 1Khz. The circuit was implemented with a 0.18um CMOS standard technology. Total current consumption is 1uA at the supply voltage of 1V with sub-threshold design technique.

Could Clinical Pathways Improve the Quality of Care in Patients with Gastrointestinal Cancer? A Meta-analysis

  • Song, Xu-Ping;Tian, Jin-Hui;Cui, Qi;Zhang, Ting-Ting;Yang, Ke-Hu;Ding, Guo-Wu
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.15 no.19
    • /
    • pp.8361-8366
    • /
    • 2014
  • This meta-analysis was performed to assess the implementation effects of clinical pathways in patients with gastrointestinal cancer. A comprehensive search was conducted in the Cochrane Library, PubMed, EMBASE, Web of Science and Chinese Biomedical Literature Database (from inception to May 2014). Selection of studies, assessing risk of bias and extracting data were performed by two reviewers independently. Outcomes were analyzed by fixed-effects and random-effects model meta-analysis and reported as mean difference (MD), standardized mean difference (SMD) and odds ratio (OR) with 95% confidence intervals (CI). The Jadad methodological approach was used to assess the quality of included studies and the meta-analysis was conducted with RevMan 5.1 software. Nine citations (eight trials) involving 642 patients were included. The aggregate results showed that a shorter average length of stay [MD = -4.0; 95% CI (-5.1, -2.8); P < 0.00001] was observed with the clinical pathways as compared with the usual care. A reduction in inpatient expenditure [SMD = -1.5; 95% CI (-2.3, -0.7); P = 0.0001] was also associated with clinical pathways, along with higher patient satisfaction [OR = 4.9; 95% CI (2.2, 10.6); P < 0.0001]. Clinical pathways could improve the quality of care in patients with gastrointestinal cancer, as evidenced by a significant reduction in average length of stay, a decrease in inpatient expenditure and an improvement in patient satisfaction. Therefore, indicators and mechanisms within clinical pathways should be a focus in the future.

Outcomes of comprehensive fixed appliance orthodontic treatment: A systematic review with meta-analysis and methodological overview

  • Papageorgiou, Spyridon N.;Hochli, Damian;Eliades, Theodore
    • The korean journal of orthodontics
    • /
    • v.47 no.6
    • /
    • pp.401-413
    • /
    • 2017
  • Objective: The aim of this systematic review was to assess the occlusal outcome and duration of fixed orthodontic therapy from clinical trials in humans with the Objective Grading System (OGS) proposed by the American Board of Orthodontics. Methods: Nine databases were searched up to October 2016 for prospective/retrospective clinical trials assessing the outcomes of orthodontic therapy with fixed appliances. After duplicate study selection, data extraction, and risk of bias assessment according to the Cochrane guidelines, random-effects meta-analyses of the mean OGS score and treatment duration were performed and 95% confidence intervals (CIs) were calculated. Results: A total of 34 relevant clinical trials including 6,207 patients (40% male, 60% female; average age, 18.4 years) were identified. The average OGS score after treatment was 27.9 points (95% CI, 25.3-30.6 points), while the average treatment duration was 24.9 months (95% CI, 24.6-25.1 months). There was no significant association between occlusal outcome and treatment duration, while considerable heterogeneity was identified. In addition, orthodontic treatment involving extraction of four premolars appeared to have an important effect on both outcomes and duration of treatment. Finally, only 10 (39%) of the identified studies matched compared groups by initial malocclusion severity, although meta-epidemiological evidence suggested that matching may have significantly influenced their results. Conclusions: The findings from this systematic review suggest that the occlusal outcomes of fixed appliance treatment vary considerably, with no significant association between treatment outcomes and duration. Prospective matched clinical studies that use the OGS tool are needed to compare the effectiveness of orthodontic appliances.

Mortality and Morbidity Based on Secondary Data Analysis for Respiratory System Diseases among Residents around Ansim, Daegu, Korea (호흡기계 질환 관련 이차자료에 근거한 대구 안심 지역주민의 사망 및 이환 현황)

  • Min, Young-Sun;Lee, Kwan;Lim, Hyun-Sul;Lee, Duk-Hee;Hong, Nam Soo;Kim, Geun-Bae
    • Journal of Korean Society of Occupational and Environmental Hygiene
    • /
    • v.25 no.3
    • /
    • pp.346-354
    • /
    • 2015
  • Objectives: This study was conducted to evaluate the changes and regional differences of mortality and morbidity particularly respiratory system diseases in the area of exposure to coal dust(Ansim area, Dong-gu, Daegu). Methods: The authors analyzed secondary data(cancer registration data, mortality data, and health insurance data) for respiratory system diseases. We calculated age standardized incidence ratio(SIR), mortality ratio(SMR), and health care utilization ratio(SHR) using those data. Results: There were no significant differences between Ansim area(or Dong-gu, Daegu) and the control area for cancer registration data and mortality data. In the results for the health insurance data, significant increased SHR in asthma was observed compared to the control area. Conclusions: Although confounders such as selection bias were not clearly ruled out, our findings reveal increased asthma SHR in the area of exposure to coal dust. Further prospective studies are required to clarify the increasing respiratory disease due to exposure to coal dust.

Learning & Growth Performance, Financial Performance, and General Performance (조직의 인적자원 학습 및 성장성과, 재무적 성과와 경영성과 간의 관계에 관한 연구)

  • Jang, Chung-Seok
    • Korean Business Review
    • /
    • v.21 no.2
    • /
    • pp.111-136
    • /
    • 2008
  • The central purpose of this study is to examine the relationships among learning and growth perspective, internal business process perspective, custom perspective, financial perspective, and general performance. To achieve this purpose, this study uses Kaplan and Norton's(1996) Balanced Scorecard Model theory. A field survey was undertaken through questionnaire sampling a population of construction companies. The data was collected from 185 firms in Korea for the analysis. The major findings of this study can be summarized as follows; Theoretical consideration and empirical study indicate statistically significant relationship(F=7.68, p=0.000). Especially, Financial perspective appeared to mediate the relationship between non-financial perspectives and general performance. It concludes that Non-financial perspectives significant affect the financial perspective and general performance. But, there are several limitations and directions for future research that should be noted. The potential limitation of this study concerns sampling and for selection process. Future research needs to reduce potential bias by collecting data which allows multiple industries for a subset of the sample.

  • PDF

A Design of Low-Power Wideband Bipolar Current Conveyor (CCII) and Its Application to Universal Instrumentation Amplifiers (저전력 광대역 바이폴라 전류 콘베이어(CCII)와 이를 이용한 유니버셜 계측 증폭기의 설계)

    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.41 no.5
    • /
    • pp.143-152
    • /
    • 2004
  • A novel low-power wideband bipolar second-generation current conveyors(CCIIs) and its application to universal instrumentation amplifier(UIA) were proposed. The CCII for accuracy voltage or current transfer characteristics and low current input impedance adopted adaptive current bias circuit into conventional class Ab CCII. The UIA consists of only two CCIIs and four resistors. Three instrumentation function of the UIA can be realized by selection of input signals and resistors. The simulation results show that the CCII has input impedance of 2.0$\Omega$ and the voltage gain of 60㏈ for frequency range from 0 to 50KHz when used as a voltage amplifier. The CCII has also good characteristics of current follower for current range from -100㎃ to +100㎃. The simulation results show that the UIA has three instrumentation amplifier functions without resistor matching. The UIA has the voltage gain of 40㏈ for frequency range from 0 to 100KHz when used as a fully-differential instrumentation amplifier. The power dissipations of the CCII and the UIA are 0.75㎽ and 1.5㎽ at supply voltage of $\pm$2.5V, respectively.

Survey on Health Effects among Workers in the Humidifier Disinfectant Manufacturing Process (가습기 살균제 제조 공정 근로자 건강영향 조사)

  • Kang, Young Joong;Park, Soon Woo;Eom, Huisu;Kim, Eun-A
    • Journal of Environmental Health Sciences
    • /
    • v.44 no.5
    • /
    • pp.409-420
    • /
    • 2018
  • Objectives: An outbreak of humidifier disinfectant-related respiratory disease has not only been a massive disaster for end users, but it is also a concern for the workers of the manufacturers. This study presents the results of a questionnaire survey on the health effects among workers involved in the manufacture of humidifier disinfectants. Methods: Seven sites where humidifier disinfectants were manufactured were identified. A questionnaire survey was conducted to assess the physical symptoms experienced by workers related to humidifier disinfectants. Among a total of 177 workers, 42 subjects were available for the survey. Results: Twenty-one of the 42 respondents reported that they experienced respiratory or skin and mucosal irritation symptoms during work. Of the respondents who experienced symptoms, 14 believed that their symptoms were related to the work process and reported that the symptoms were experienced while working. However, no respondents reported ongoing symptoms or sequelae during the investigation period, and this result could not minimize selection bias due to low response rates. We then compared the characteristics of the group who experienced suspicious symptoms with those of the group without any symptoms. There was no statistically significant difference between two groups. Conclusions: We could not find significant health effects related to the humidifier disinfectant manufacturing process, although 21 respondents experienced stimulant symptoms and 14 respondents believed that the symptoms were related to the work process. Due to the long period of time after occupational exposure and the lack of data, there were many limitations to this study. However, this is one of the few follow-up investigations of workers related to this large-scale disaster in South Korea and the limitations of this study highlight the need to follow up with a nationwide database rather than an occasional survey.

A study on the professional ethical relationship between librarian and library work (도서관 업무와 전문사서간의 윤리적 관계에 관한 이론적 고찰)

  • 손연옥
    • Journal of Korean Library and Information Science Society
    • /
    • v.24
    • /
    • pp.485-517
    • /
    • 1996
  • The purpose of this study is to investigate typical ethical problems found in the technical and public services areas. The followings are the summary of the study. There are three distinct elements that govern ethical problems. One element is legal laws. The copyright law and the privacy act are exact examples. The copyright law has strong influence on the inter library loan service where the majority requests from the users are reproduction of copies. The privacy act also creates difficulties for librarians. Most requests for circulation records infringe on the privacy of library user. And advance online access systems also violates the privacy of library users. The second element is the code or rules that private organization has created. American Library Association created many statements that regulate the conduct of librarians. The bill of right, the professional code of ethics and policy on the confidentiality of library records have strong implications in the obligation of librarian. In the case of censorship at the selection of library materials, the code is a defensive tool against intellectual freedom. Yet self-censoring are prevailing practice among librarians. The thirds element is the competence of librarians. The analyzed table 3 showed that beside two elements, the rest of matters are competence required by librarians. The one aspect of it is humaneness and the other one is technical aspects. Technical aspect of competence are:(l) managerial and operational ability (2) communication skill (3) leadership (4) structure of knowledge and (5) self developing professionalism. Humanity aspect of competence are:(l) trust(fiduciary relationship) gained by diligence, objective judgement, ability, belief, rationality, integrity, kindness) (2) objectiveness (free from bias) (3) user-oriented consideration (need, interest, equal treatment, information gap) (4) caution in providing information (5) pride and (6) ability to distinguish advice and guidance specially in medical and law library.

  • PDF

Effects and Causality of Measures for Personal Information: Empirical Studies on Firm and Individual Behaviors and their Implications (개인정보보호 대책의 효과 및 인과관계: 기업 및 개인의 개인정보보호 행동에 대한 실증분석 및 그 시사점)

  • Shin, Ilsoon
    • Journal of the Korea Institute of Information Security & Cryptology
    • /
    • v.26 no.2
    • /
    • pp.523-531
    • /
    • 2016
  • This paper studies the empirical relationship between various privacy protection measures and personal information invasion experience of firms and individuals using rich and heterogeneous survey data. By analyzing PSM models. we get the following results: first, the treatment group which have more technical measures and/or IS investment tends to experience more privacy invasion than the control group which have less of them. second, the reverse causality, that is firms and individuals with more experience of privacy invasion tends to take more measure for personal information protection, is found to exist. From these result, we discuss proper privacy policies implications in respects of attackers benefits and individual irrationality.

Hepatotoxic Events Associated with Herbal Medicinal Products, Folk Remedies and Food Supplements in Korea (국내에서 보고된 한약 및 민간요법, 건강식품 관련 약인성간손상에 대한 체계적 고찰)

  • Park, Hae-Mo;Jang, In-Soo;Lee, Sun-Dong
    • The Journal of Korean Medicine
    • /
    • v.26 no.2 s.62
    • /
    • pp.152-165
    • /
    • 2005
  • Background: The use of herbal preparations as remedies for various medical conditions has continuously increased in Korea Large proportions of Korean patients use herbal medicinal products, folk remedies, and food supplements. However, studies on the safety of herbal products arc conducted on a less than sufficient basis even in the countries like Korea where herbal medicine is being used extensively. Some of the reports on the safety of herbs were done by the doctors of western medicine but lack of knowledge and misclassification led to misunderstandings. Objecitves: This study aims to review the recent evidences on hepatotoxic events associated with the use of herbal medicinal products, folk remedy, and food supplements. In the process, this review will grasp trends in this field of studies and will direct further researches into the right direction. Methods: Systematic literature searches were performed on MedRic and MEDLIS in Korea. Screening and selection of the articles and the extraction of data were performed independently by two of authors. There were no restrictions regarding the published date. In order to avoid bias, the articles written by medical doctors, not by oriental doctors were selected. 43 journals were chosen for the review. Results: Analyzing the number of journals, studies on the drug-induced liver injury were increased after the year 2000. The proportion of herbal and folk remedy associated hepatotoxic injuries in all drug-induced liver injury was $21.0\%-30.0\%$. But criterion for herbal medicine is rather vague and limited objective data hindered objectiveness. Few of single medicinal herbs and combination preparations were associated with hepatotoxic injuries. But because of lack of objectivity, further researches must be conducted to yield more concrete results. Conclusions: yield more concrete results. Incidence figures are largely unknown, and in most cases a causal attribution is not established. The challenge for the future is to systematically research this area, educate all parties involved, and minimize patient risks.

  • PDF