• Title/Summary/Keyword: response bias

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A Posterior Preference Articulation Method to the Weighted Mean Squared Error Minimization Approach in Multi-Response Surface Optimization (다중반응표면 최적화에서 가중평균제곱오차 최소화법을 위한 선호도사후제시법)

  • Jeong, In-Jun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.10
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    • pp.7061-7070
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    • 2015
  • Multi-Response Surface Optimization aims at finding the optimal setting of input variables considering multiple responses simultaneously. The Weighted Mean Squared Error (WMSE) minimization approach, which imposes a different weight on the two components of mean squared error, squared bias and variance, first obtains WMSE for each response and then minimizes all the WMSEs at once. Most of the methods proposed for the WMSE minimization approach to date are classified into the prior preference articulation approach, which requires that a decision maker (DM) provides his/her preference information a priori. However, it is quite difficult for the DM to provide such information in advance, because he/she cannot experience the relationships or conflicts among the responses. To overcome this limitation, this paper proposes a posterior preference articulation method to the WMSE minimization approach. The proposed method first generates all (or most) of the nondominated solutions without the DM's preference information. Then, the DM selects the best one from the set of nondominated solutions a posteriori. Its advantage is that it provides an opportunity for the DM to understand the tradeoffs in the entire set of nondominated solutions and effectively obtains the most preferred solution suitable for his/her preference structure.

Effect of cassia cinnamon intake on improvement of the glycemic response: An updated meta-analysis - Focus on preparation of dehydrated powder and water extract (계피의 혈당 개선 기능성 평가 : 메타분석 - 건조분말과 물추출물을 중심으로)

  • Kwak, Jin Sook;Park, Min young;Kwon, Oran
    • Journal of Nutrition and Health
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    • v.50 no.5
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    • pp.437-446
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    • 2017
  • Purpose: This meta-analysis aimed to evaluate the effect of cassia cinnamon (Cinnamomum. cassia and C. aromaticum) on the glycemic response with a focus on the preparation of dehydrated powder and water extract. Methods: We searched Pubmed, Cochrane, EMBASE, Science Direct, and the Korean Studies Information Service System (KISS) through May 2017. In the meta-analysis for the preparation of powder, eight trials reporting fasting blood glucose (FBG), four trials reporting HbA1c, and three trials reporting the postprandial glycemic response were included. For the water extract, six trials reporting FBG and four trials reporting HbA1c were eligible for this study. A random-effects model was used to calculate the pooled effect size. Results: Cassia cinnamon powder intake significantly lowered FBG by -1.55 mmol/L (95% CI, -2.45, -0.64; p = 0.001) and the AUC of postprandial blood glucose level by $-51.8mmol/L{\cdot}min$ (95% CI, -85.5, -18.1; p = 0.003). There was a significant difference in FBG between water extract of cinnamon and placebo of -0.76 mmol/L (95% CI, -1.09, -0.43; p = 0.000). However, blood HbA1c level was not significantly altered by any preparation of cinnamon. No statistical heterogeneity was observed for any analysis except in the case of FBG for cinnamon powder. Results of funnel plots and Egger's regression suggest a low likelihood of publication bias in all biomarkers (p > 0.05). Conclusion: According to this meta-analysis, there was possible evidence to support a relationship between cassia cinnamon intake and fasting glucose in both preparation of powder and water extract. Furthermore, new evidence of the health benefits on postprandial glucose regulation of cinnamon powder was obtained.

ccuracy Evaluation of MSD-related Risky Work Criterion of Korea Ministry ofLabor using Ergonomic Workload Evaluation Methods (인간공학적 작업부하 평가방법을 이용한 근골격계 부담작업 판정기준의 정확성 평가)

  • Park, Guk-Mu;Jeong, Min-Geun;Gi, Do-Hyeong;Ryu, Tae-Beom
    • Journal of the Ergonomics Society of Korea
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    • v.25 no.2
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    • pp.119-124
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    • 2006
  • The present study evaluated the accuracy of MSD-related work criterion of Korea Ministry of Labor by using ergonomic workload evaluation methods. 1,948 manufacturing works in automobile industry were divided into 1,286 MSD-related risky works and 662 risk-free ones by using RULA, ANSI Z-365 and perceived discomfort evaluation. Then, the two types of works were evaluated by Labor Ministry work criterion to analyze the classification accuracy of the work criterion. The work criterion of Korea Labor Ministry had low hit and false alarm ratio(20 and 11%) and high miss and correct rejection ratio(80 and 89%), and the odd ratios of hit and correct rejection were 0.2 and 8.3, respectively. It can be concluded that the work criterion of Korea Labor Ministry is a conservative evaluation method which tends to evaluate a target work as risk-free.

Exchange Anisotropy of Polycrystalline Ferromagnetic/Antiferromagnetic Bilayers

  • Tsunoda, Masakiyo;Takahashi, Migaku
    • Journal of Magnetics
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    • v.7 no.3
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    • pp.80-93
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    • 2002
  • The role of magnetic anisotropy of the antiferromagnetic layer on the magnetization process of exchange coupled polycrystalline ferromagnetidantiferromagnetic bilayers is discussed. In order to elucidate the magnetic torque response of Ni-Fe/Mn-Ir bilayers, the single spin ensemble model is newly introduced, taking into account the two-dimensionally random distribution of the magnetic anisotropy axes of the antiferromagnetic grains. The mechanism of the reversible inducement of the exchange anisotropy along desirable directions by field cooling procedure is successfully explained with the new model. Unidirectional anisotropy constant, J$k$, of polycrystalline Ni-Fe/Mn-Ir and Co-Fe/Mn-Ir bilayers is investigated as functions of the chemical composition of both the ferromagnetic layer and the antiferromagnetic layer. The effects of microstructure and surface modification of the antiferromagnetic layer on JK are also discussed. As a notable result, an extra large value of J$k$, which exceeds 0.5 erg/cm$^2$, is obtained for $Co_{70}Fe_{30}Mn_{75}Ir_{25}$ bilayer with the ultra-thin (50${\AA}$∼100${\AA}$) Mn-Ir layer. The exchange anisotropy of $Co_{70}Fe_{30}$ 40 ${\AA}/Mn_{75}Ir_{25}$ 100 ${\AA}$ bilayer is stable for thermal annealing up to $400{^{\circ}C}$, which is sufficiently high for the application of spin valve magnetoresistive devices.

Ultrafast and flexible UV photodetector based on NiO

  • Kim, Hong-sik;Patel, Malkeshkumar;Kim, Hyunki;Kim, Joondong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.389.2-389.2
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    • 2016
  • The flexible solid state device has been widely studied as portable and wearable device applications such as display, sensor and curved circuits. A zero-bias operation without any external power consumption is a highly-demanding feature of semiconductor devices, including optical communication, environment monitoring and digital imaging applications. Moreover, the flexibility of device would give the degree of freedom of transparent electronics. Functional and transparent abrupt p/n junction device has been realized by combining of p-type NiO and n-type ZnO metal oxide semiconductors. The use of a plastic polyethylene terephthalate (PET) film substrate spontaneously allows the flexible feature of the devices. The functional design of p-NiO/n-ZnO metal oxide device provides a high rectifying ratio of 189 to ensure the quality junction quality. This all transparent metal oxide device can be operated without external power supply. The flexible p-NiO/n-ZnO device exhibit substantial photodetection performances of quick response time of $68{\mu}s$. We may suggest an efficient design scheme of flexible and functional metal oxide-based transparent electronics.

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An Adaptive Fast Image Restoration Filter for Reducing Blocking Artifacts in the Compressed Image (압축 영상의 블록화 제거를 위한 적응적 고속 영상 복원 필터)

  • 백종호;이형호;백준기;윈치선
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 1996.06a
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    • pp.223-227
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    • 1996
  • In this paper we propose an adaptive fast image restoration filter, which is suitable for reducing the blocking artifacts in the compressed image in real-time. The proposed restoration filter is based on the observation that quantization operation in a series of coding process is a nonlinear and many-to-one mapping operator. And then we propose an approximated version of constrained optimization technique as a restoration process for removing the nonlinear and space varying degradation operator. We also propose a novel block classification method for adaptively choosing the direction of a highpass filter, which serves as a constraint in the optimization process. The proposed classification method adopts the bias-corrected maximized likelihood, which is used to determine the number of regions in the image for the unsupervised segmentation. The proposed restoration filter can be realized either in the discrete Fourier transform domain or in the spatial domain in the form of a truncated finite impulse response (FIR) filter structure for real-time processing. In order to demonstrate the validity of the proposed restoration filter experimental results will be shown.

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Electro-Optical Characteristics of the Ion-Beam-Aligned FFS-LCD on a Diamond-like-Carbon Thin Film

  • Hwang, J.Y.;Park, C.J.;Seo, D.S.;Jeong, Y.H.;Kim, K.C.;Ahn, H.J.;Baik, H.K.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.1132-1136
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    • 2004
  • In this paper, we intend to make FFS mode cell with LC alignment used non-rubbing method, ion beam alignment method on the a-C:H thin film, to analyze electro-optical characteristics in this cell. We studied on the suitable inorganic thin film for FFS-LCD and the aligning capabilities of nematic liquid crystal (NLC) using the new alignment material of a-C:H thin film as working gas at rf bias condition. A high pretilt angle of about 5$^{\circ}$ by ion beam(IB) exposure on the a-C:H thin film surface was measured. An excellent voltage-transmittance (V-T) and response time curve of the ion-beam-aligned FFS-LCD was observed with oblique ion beam exposure on the DLC thin films.

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The Cross Cultural Adaptation For Neck Disability Questionnaires (목 기능장애 설문지의 절충 문화 적응)

  • Lim Chang-hun;Lee Hae-jung;Bae Sung-soo;Kim Jin-sang
    • The Journal of Korean Physical Therapy
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    • v.17 no.2
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    • pp.46-66
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    • 2005
  • With the increase in the number of multinational and multicultural research projects, the need to adapt health status measures for use in other than source language has also grown rapidly. Most questionnaire were developed in English-speaking countries, but even within these countries, researchers must consider immigrant populations in studies of health, especially when their exclusion could lead to a systematic bias in studies of health care utilization or quality of life. The purpose of this study was to translate and and culturally adapt the three most used neck and spinal pain disability questionnaires - the Neck Disability Index(NDI), Neck pain and Disability Scale(NPDS), and Functional Rating Index(FRI) - into the korean language and evaluated their reliability, in addition to item response pattern, to achieve a good cross cultural adaptation. Each translated questionnaire was found to have high reliability (FRI ICC (2,1)=0.86 ($95\%$ CI: 0.75-0.92); NPDS ICC (2,1)=0.90 ($95\%$ CI: 0.83-0.95 ; NDI ICC (2,1) =0.90 ($95\%$ CI: 0.81-0.94)). The reliability of the translated versions of FRI, NPDS and NDI were excellent.

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Effect of Age on Judgment in Driving: A Simulation Study (운전 수행에서 판단의 정확성에 미치는 연령의 효과: 운전 시뮬레이션 연구)

  • Lee, Joon-Bum;Kim, Bi-A;Lee, Se-Won;Lee, Jae-Sik
    • Journal of the Korean Society of Safety
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    • v.23 no.2
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    • pp.45-50
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    • 2008
  • The purpose of the present study was to investigate the age difference in driving behavior(more specifically, left-turn). The participants were instructed to report whether they can turn left their car in the T-shape road(road and other vehicles' behavior relating to driver's tasks were recorded in advance and projected the simulation screen) after the leading vehicle passed them(i.e., before the target vehicle arrived). The participants' judgment accuracy and response bias were analyzed by using signal detection theory. The results showed that the old group tended to be less sensitive but more confident in their judgement of turning left their car. In particular, both age groups appeared to more depend on the distance from observation location to approaching vehicle rather than arrival times or driving speeds of the approaching vehicle.

A Quantitative Vigilance Measuring Model by Fuzzy Sets Theory in Unlimited Monitoring Task

  • Liu, Cheng-Li;Uang, Shiaw-Tsyr;Su, Kuo-Wei
    • Industrial Engineering and Management Systems
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    • v.4 no.2
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    • pp.176-183
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    • 2005
  • The theory of signal detection has been applied to a wide range of practical situation for a long time, including sonar detection, air traffic control and so on. In general, in this theory, sensitivity parametric index d' and bias parametric index $\beta$ are used to evaluated the performance of vigilance. These indices use observer's response "hit" and "false alarm" to explain and evaluate vigilance, but not considering reaction time. However, the reaction time of detecting should be considered in measuring vigilance in some supervisory tasks such as unlimited monitoring tasks (e.g., supervisors in nuclear plant). There are some researchers have used the segments of reaction time to generate a pair of probabilities of hit and false alarm probabilities and plot the receiver operating characteristic curve. The purpose of this study was to develop a quantitative vigilance-measuring model by fuzzy sets, which combined the concepts of hit, false alarm and reaction time. The model extends two-values logic to multi-values logic by membership functions of fuzzy sets. A simulated experiment of monitoring task in nuclear plant was carried out. Results indicated that the new vigilance-measuring model is more efficient than traditional indices; the characteristics of vigilance would be realized more clearly in unlimited monitoring task.