• Title/Summary/Keyword: negative bias

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Issues in Applying CV Methods to the Preliminary Feasibility Test (예비타당성조사 적용 CVM의 분석체계와 개선과제)

  • Eom, Young Sook;Kwon, Oh-Sang;Shin, Youngchul
    • Environmental and Resource Economics Review
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    • v.20 no.3
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    • pp.595-628
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    • 2011
  • This study investigates the issues and suggests reform measures in applying CV methods to the Korea Development Institute's (KDI's) Preliminary Feasibility Test (PFT) of public projects. Most public projects on culture, science and environment evaluated under the PFT system belong to the category of "nonstandard" projects whose outputs are non-marketed, and CV is currently the main tool used for their benefit estimation. A careful discussion and investigation is recommended for the selection of target population, payment vehicle, and number of payment times. Operating expert reviews, focus group interviews, and pre-tests is highly recommended to reduce the potential bias involved in the CV studies. A single or double bounded dichotomous choice format is the most popular design of questionnaire, but we identify several undissolved issues in designing and implementing the format. Some other forms of inducing WTPs may still deserve our consideration. Various specifications of the WTP function need to be tried and tested based on their stability, in particular. Employing a nonparametric approach is also recommended. Treatments of 0 or negative WTPs and protest bids are shown to be the most serious issues that affect the estimation results significantly. We review diverse measures of handling those issues and summarize their advantages and shortcomings.

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Rereading World Geography Textbooks in Terms of Global Education: An Analysis of Korea in US World Geography Textbooks (세계 시민 교육의 관점에서 세계 지리 교과서 다시 읽기: 미국 세계 지리 교과서 속의 '한국')

  • Noh, Hae-Jeong
    • Journal of the Korean Geographical Society
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    • v.43 no.1
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    • pp.154-169
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    • 2008
  • Geography textbooks often have treated the world as a collection of independent nations. Also, many scholars have warned of ethnocentric bias in geography textbooks. Global education that emphasizes world interdependence and pursues global perspectives offers some possibilities to go beyond the status quo of current World Geography textbooks. The primary objective of this study is to analyze current US World Geography textbooks in terms of global education. A secondary objective is to explore a framework for rereading World Geography textbooks critically. This interpretive qualitative case study indicates that US World Geography textbooks maintain an imperialist and American-centered perspective. Especially, the case of Korea shows that other places and people are underrepresented through dichotomy, negative attitude and exclusion, misconception and stereotyping, and simplification in textbooks. Therefore, we need to detect conscious and unconscious fallacy and bias, to understand the world view and experiences of underrepresented people, and to deal with controversial global issues from diverse perspectives through global perspectives and post-colonial perspectives of global education.

The Differential Effects of Transformational Leadership and Organizational Justice on Work Engagement : the Mediating Role of Psychological Contract Breach (변혁적 리더십 및 조직 공정성이 직무열의에 미치는 차별적 영향 : 심리적 계약위반의 매개효과)

  • Baec, Chae-Yoon;Shin, Je-Goo
    • The Journal of the Korea Contents Association
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    • v.17 no.1
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    • pp.299-336
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    • 2017
  • The purpose of this study is to identify the differential effects of transformational leadership and organizational justice on psychological contract breach and work engagement, and to suggest practical implications. To this purpose, this study theoretically references equity theory which recognizes the relationship between organizational input and output, social exchange theory which explains the exchange relationship between members and organization, and job demand-resource (JD-R) model that combines job demands and job resources. A empirical study was conducted on 277 employees at 18 companies of diverse industries including manufacturing, distribution, and finance, and to eliminate the common method bias problem, the dependent variable was measured using peer evaluation. The results of this study showed that: 1) both transformational leadership and organizational justice had a significant positive effect on work engagement and significant negative effect on psychological contract breach; and 2) psychological contract breach played a partial mediating role in the relationship between transformational leadership and work engagement as well as between organizational justice and work engagement. Therefore, this study suggests that, as organizational justice has stronger influence on work engagement and psychological contract breach than transformational leadership, organizations should not only train its leaders but also guarantee fairness.

Degradation from Polishing Damage in Ferroelectric Characteristics of BLT Capacitor Fabricated by Chemical Mechanical Polishing Process (화학적기계적연마 공정으로 제조한 BLT Capacitor의 Polishing Damage에 의한 강유전 특성 열화)

  • Na, Han-Yong;Park, Ju-Sun;Jung, Pan-Gum;Ko, Pil-Ju;Kim, Nam-Hoon;Lee, Woo-Sun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.236-236
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    • 2008
  • (Bi,La)$Ti_3O_{12}$(BLT) thin film is one of the most attractive materials for ferroelectric random access memory (FRAM) applications due to its some excellent properties such as high fatigue endurance, low processing temperature, and large remanent polarization [1-2]. The authors firstly investigated and reported the damascene process of chemical mechanical polishing (CMP) for BLT thin film capacitor on behalf of plasma etching process for fabrication of FRAM [3]. CMP process could prepare the BLT capacitors with the superior process efficiency to the plasma etching process without the well-known problems such as plasma damages and sloped sidewall, which was enough to apply to the fabrication of FRAM [2]. BLT-CMP characteristics showed the typical oxide-CMP characteristics which were related in both pressure and velocity according to Preston's equation and Hernandez's power law [2-4]. Good surface roughness was also obtained for the densification of multilevel memory structure by CMP process [3]. The well prepared BLT capacitors fabricated by CMP process should have the sufficient ferroelectric properties for FRAM; therefore, in this study the electrical properties of the BLT capacitor fabricated by CMP process were analyzed with the process parameters. Especially, the effects of CMP pressure, which had mainly affected the removal rate of BLT thin films [2], on the electrical properties were investigated. In order to check the influences of the pressure in eMP process on the ferroelectric properties of BLT thin films, the electrical test of the BLT capacitors was performed. The polarization-voltage (P-V) characteristics show a decreased the remanent polarization (Pr) value when CMP process was performed with the high pressure. The shape of the hysteresis loop is close to typical loop of BLT thin films in case of the specimen after CMP process with the pressures of 4.9 kPa; however, the shape of the hysteresis loop is not saturated due to high leakage current caused by structural and/or chemical damages in case of the specimen after CMP process with the pressures of 29.4 kPa. The leakage current density obtained with positive bias is one order lower than that with negative bias in case of 29.4 kPa, which was one or two order higher than in case of 4.9 kPa. The high pressure condition was not suitable for the damascene process of BLT thin films due to the defects in electrical properties although the better efficiency of process. by higher removal rate of BLT thin films was obtained with the high pressure of 29.4 kPa in the previous study [2].

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The effectiveness and safety of acupuncture combination treatment on smoking cessation: A protocol for systematic review (금연에 대한 침술 병용 치료의 효과 및 안전성 : 체계적 검토를 위한 프로토콜)

  • In Suh Choi;Won-Suk Sung;Min-gi Jo;Jung-Hyun Kim;Yeon-Cheol Park;Eun-Jung Kim;Yong-Hyeon Baek;Geun-Woo Kim;Byung-Kwan Seo
    • Journal of Convergence Korean Medicine
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    • v.3 no.1
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    • pp.5-13
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    • 2022
  • Objectives: Smoking had a long negative impact on public health. The ingredients of a cigarette are major risk factors for several diseases. Owing to the problems about economic and quality of life, we need to ensure smoking cessation (SC). There are several approaches for SC including pharmacological therapy, nicotine replacement therapy, education, and behavioral intervention. However, due to some limitations, other alternative approaches are gaining popularity. Acupuncture has been reported to have few side effects and be more effective than some conventional treatments in several articles. However, there are no systematic reviews on the comparison of acupuncture combination treatment with other conventional monotherapies. Methods: Randomized controlled trials that used acupuncture as an adjunct treatment for SC will be searched and data will be summarized according to the predefined criteria. The primary outcome will be the abstinence rate, and secondary outcomes will be adverse events and biochemical indicators. We will use Review Manager to perform a meta-analysis, Cochrane Collaboration Risk of Bias tool for the risk of bias assessment, and the Grades of Recommendation, Assessment, Development and Evaluation approach to determine the quality of evidence. We will investigate the efficacy and safety of acupuncture combination treatment for SC with this study. Ethics and dissemination: This study will provide reliable clinical evidence on additional effect of acupuncture on smoking cessation. We will publish our results in a peer-review journal.

The Effects of Corner Transistors in STI-isolated SOI MOSFETs

  • Cho, Seong-Jae;Kim, Tae-Hun;Park, Il-Han;Jeong, Yong-Sang;Lee, Jong-Duk;Shin, Hyung-Cheol;Park, Byung-Gook
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.615-618
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    • 2005
  • In this work, the effects of corner transistors in SOI MOSFETs were investigated. We fabricated SOI MOSFETs with various widths and a fixed length and characterized them. The SOI thickness was $4000{\AA}$ and the buried oxide(BOX) thickness was $4000{\AA}$. The isolation of active region was simply done by silicon etching and TEOS sidewall formation. Several undesirable characteristics have been reported for LOCOS isolation in fabrication on SOI wafers so far. Although we used an STI-like process instead of LOCOS, there were still a couple of abnormal phenomena such as kinks and double humps in drain current. Above all, we investigated the location of the parasitic transistors and found that they were at the corners of the SOI in width direction by high-resolution SEM inspection. It turned out that their characteristics are strongly dependent on the channel width. We made a contact pad through which we can control the body potential and figured out the dependency of operation on the body potential. The double humps became more prominent as the body bias went more negative until the full depletion of the channel where the threshold voltage shift did not occur any more. Through these works, we could get insights on the process that can reduce the effects of corner transistors in SOI MOSFETs, and several possible solutions are suggested at the end.

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Header-Based Power Gating Structure Considering NBTI Aging Effect (NBTI 노화 효과를 고려한 헤더 기반의 파워게이팅 구조)

  • Kim, Kyung-Ki
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.49 no.2
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    • pp.23-30
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    • 2012
  • This paper proposes a novel adaptive header-based power gating structure to compensate for the performance loss and the increased wake-up time of the power gating structures induced by the negative bias temperature instability (NBTI) effect. The proposed structure consists of variable width footers based on the two-pass power gating and a new NBTI sensing circuit for an adaptive control. The simulation results of the proposed structure are compared to those of power gating without the adaptive control and show that both the circuit-delay and wake-up time dependence of the power gating structure on the NBTI stress is minimized with only 3% and 4% increase, respectively while keeping small leakage power and rush-current. In this paper, a 45 nm CMOS technology and predictive NBTI model have been used to implement the proposed circuits.

Broadband VCO Using Electronically Controlled Metamaterial Transmission Line Based on Varactor-Loaded Split-Ring Resonator (Varactor-Loaded Split-Ring Resonator(VLSRR) 기반의 가변 Metamaterial 전송 선로를 이용한 광대역 전압 제어 발진기)

  • Choi, Jae-Won;Seo, Chul-Hun
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.11
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    • pp.54-59
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    • 2007
  • In this paper, broadband voltage-controlled oscillator (VCO) using electronically controlled metamaterial transmission line based on varactor-loaded split-ring resonator (VLSRR) is presented. First, it is demonstrated that VLSRR coupled to microstrip line can lead to metamaterial transmission line with tuning capability. The negative effective permeability is provided by the VLSRR in a narrow band above the resonant frequency, which can be bias controlled by virtue of the presence of varactor diodes. The VCO with 1.8 V power supply has phase noise of $-108.84\;{\sim}\;-106.84\;dBc/Hz$ @ 100 Hz in the tuning range, $5.47\;{\sim}\;5.84\;GHz$. The figure of merit (FOM) called power-frequency-tuning-normalized (PFTN) is 20.144 dB.

Computational Study on the Hemodynamics of Cardiovascular System Including Short-term Auto-regulation Functions (단기적 자율조절기능을 포함하는 심혈관계 혈류역학 모델링에 관한 수치적 연구)

  • 심은보;정찬일;최한고
    • Journal of Biomedical Engineering Research
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    • v.22 no.5
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    • pp.393-402
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    • 2001
  • A computational model representative of cardiovascular circulation was built using 12 standard lumped compartments. Especially, both the baroreceptor reflex and the cardiopulmonary reflex control model were implemented to explain the auto-regulation of cardiovascular system. Another important aspect of this model is to utilize the impulse-response curve of the nerve system in transferring the impulse error signals to autonomous nerve system. For the verification of this model, we have computed the normal hemodynamic conditions and compared those with the clinical data. Then. hemodynamic shock of 20% hemorrhage to cardiovascular system was simulated to test the effects of the control system model. The results of these two simulations were well matched with the experimental ones. The steady state LBNP simulation was also performed. The transient changes of hemodynamic variables due to ramp increase of bias pressure of LBNP showed good agreement with the physiological experiments. Numerical solution using only the baroreflex model showed relatively a larger deviation from the experimental data. compared with the one using the control model haying both the baroreflex and the cardiopulmonary reflex systems, which shows an important role of the cardiopulmonary reflex system for the simulation of the hemodynamic behavior of the cardiovascular system .

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