• Title/Summary/Keyword: Data Bias

Search Result 1,766, Processing Time 0.027 seconds

Discrimination of Private Property Right Protection in the U.S. Urban Regeneration Projects: A Perspective of Legal Geography (미국 도시재생사업과 사유재산권 보호의 차별 - 법제지리학의 관점 -)

  • Kim, Yong-Chang
    • Journal of the Korean Geographical Society
    • /
    • v.47 no.2
    • /
    • pp.245-267
    • /
    • 2012
  • This paper analyzes the discrimination of private property right protection in urban regeneration projects that is implemented by eminent domain based on public use in the United States. In spite of urban regeneration projects which depends on property condemnation for public use as a coercive power, it is executed on the discrimination of property right and sacrifice of the social disadvantages that transfer property from these private party to another big capitals and private developers. At first this paper investigates research trends in urban regeneration within the framework of multidisciplinary approach and suggests legal geographical perspective as a new research field. Next I figure out current state, types and numbers of brownfields site with the EPA and GAO data, and define these sites as results of deindustrialization and suburbanization process. Finally this paper uncover that the discrimination process of private property right is due to complex actions of expansion of public use concept in the U.S. Supreme Court from public ownership to economic public use, privatization of eminent domain, growth coalition regime and business friendly policy focused on economic development, class and racial bias, neoliberal movements of property right reform.

  • PDF

Convergence Study of Laughter Therapy's Effects on Depression among Older Adults in Korea: A Meta-Analysis (웃음치료가 노인 우울에 미치는 효과에 관한 융합연구: 메타분석)

  • Do, Eunna;Cho, Sunhee;Kim, Sun Kyung
    • Journal of the Korea Convergence Society
    • /
    • v.9 no.6
    • /
    • pp.347-355
    • /
    • 2018
  • A convergence study was conducted to identify effect size, intervention characteristics, and tendency of laughter therapies on depression for Korean older adults. Of the 486 studies searched in 10 databases, 20 studies in the inclusion criteria were selected. The risk of bias was assessed by SIGN's tool, and the data were analyzed using CMA 3.0 software. Overall effect size of laughter therapy on depression of older adults was medium (standardized mean difference [SMD]=-0.57, 95% CI: -0.70~-0.44, p<.001), and heterogeneity was small ($I^2=18%$). Subgroup analysis showed that the effect sizes of institutionalized group, mixed group, 4-6 weeks of duration, and group intervention were higher than the compared groups. Findings of this convergent meta-analysis would be helpful for health professionals to provide more effective laugher therapy sessions. Further replicative studies in long-term care facilities and more randomized controlled trials of laughter therapy are needed.

Mapping Studies on Visual Search, Eye Movement, and Eye track by Bibliometric Analysis

  • Rhie, Ye Lim;Lim, Ji Hyoun;Yun, Myung Hwan
    • Journal of the Ergonomics Society of Korea
    • /
    • v.34 no.5
    • /
    • pp.377-399
    • /
    • 2015
  • Objective: The aim of this study is to understand and identify the critical issues in vision research area using content analysis and network analysis. Background: Vision, the most influential factor in information processing, has been studied in a wide range of area. As studies on vision are dispersed across a broad area of research and the number of published researches is ever increasing, a bibliometric analysis towards literature would assist researchers in understanding and identifying critical issues in their research. Method: In this study, content and network analysis were applied on the meta-data of literatures collected using three search keywords: 'visual search', 'eye movement', and 'eye tracking'. Results: Content analysis focuses on extracting meaningful information from the text, deducting seven categories of research area; 'stimuli and task', 'condition', 'measures', 'participants', 'eye movement behavior', 'biological system', and 'cognitive process'. Network analysis extracts relational aspect of research areas, presenting characteristics of sub-groups identified by community detection algorithm. Conclusion: Using these methods, studies on vision were quantitatively analyzed and the results helped understand the overall relation between concepts and keywords. Application: The results of this study suggests that the use of content and network analysis helps identifying not only trends of specific research areas but also the relational aspects of each research issue while minimizing researchers' bias. Moreover, the investigated structural relationship would help identify the interrelated subjects from a macroscopic view.

The Study on the Comparative Analysis of the Aquaculture Production Efficiency Regarding Methods and Species (양식업의 양식방법별 어종별 생산효율성 비교분석에 관한 연구)

  • Park, Cheol-Hyung
    • The Journal of Fisheries Business Administration
    • /
    • v.43 no.2
    • /
    • pp.79-94
    • /
    • 2012
  • The purpose of this study is to investigate the production efficiencies of the Korean aquaculture fishery with respect to species and methods using a Data Envelopment Analysis. The study extracted the 8 fishes in each of the sea cage culture, aquarium basin, and enclosed aquaculture for the analytical purposes. First, the study estimated the technical, pure technical, and scale efficiencies of the total of 24 aquaculture fishes based on the traditional DEA under the assumptions of both CRS and VRS. 2 fishes were identified as the efficient DMUs under the CCR-model, and 6 fishes under the BCC-model. Second, we tested to see if there was any difference in production efficiencies regarding those three different methods of aquaculture. we could not find any evidence of the differences in efficiency using a rank sum test based on the traditional DEA. However, we could do find that the pure technical efficiency in the sea cage culture was lower than others at 1% level of significance and the pure technical efficiency in enclosed aquaculture was also lower than others at 5% level of significance using Bilateral-DEA, which could explicitly consider the heterogeneity in the 3 production methods of aquaculture. Finally, the study obtained the 95% confidence intervals of the efficiency scores for the 24 fishes under our study using the smoothed bootstraping method in the process of the re-sampling in cooperation with both a kernel density estimation and a reflection method. At the same time, we could estimate the bias-corrected efficiency scores while the traditionally estimated efficiency scores suffered from the biases in the process of solving a linear programming with the deterministic nature of a production frontier. And hence, we could distinguish the differences in production efficiencies of the 8 fishes with respect to those 3 methods of aquaculture.

CHARACTERISTICS OF THE FAIRCHILD 486 CCD AT MAIDANAK ASTRONOMICAL OBSERVATORY IN UZBEKISTAN (우즈베키스탄 Maidanak 천문대 Fairchild 486 CCD의 기본적인 특성)

  • Lim, Beom-Du;Sung, Hwan-Kyung;Karimov, R.;Ibrahimov, M.
    • Publications of The Korean Astronomical Society
    • /
    • v.23 no.1
    • /
    • pp.1-12
    • /
    • 2008
  • Understanding of the basic characteristics of an astronomical instrument is a prerequisite to obtaining reliable data from the instrument. We have analyzed more than 1,000 calibration images from the Fairchild 486 CCD (hereafter the Maidanak 4k CCD system) attached to the AZT-22 1.5m telescope at Maidanak Astronomical Observatory in Uzbekistan. The Maidanak 4k CCD system supports three readout modes through 1, 2, or 4 amplifiers. In most cases observers use 4-amplifier readout mode to save time. We have tested the stability and seasonal variation of zero levels and confirm that two quadrants of the images (Amp 1 & 2) show no appreciable seasonal variation. but the other two quadrants (Amp 3 & Amp 4) show an evident seasonal variation in the bias level. The Cryo Tiger, the cooling system used at the Maidanak 4k CCD system, maintains the CCD temperature at -108'E, and effectively suppresses the dark electrons. The mean value versus the variance plot of the flat images does not show the expected relation for an ideal Poisson noise distribution and this is attributed to the large variation in quantum efficiency between different pixels. In addition, we confirm that there is no appreciable difference in gain between readout amplifiers, but there is a large variation in quantum efficiency across CCD chip especially in U. Due to the finite length of shutter opening and closing time, the effective exposure time varies across the science images. We introduce two parameters to quantify the effect of this uneven illumination and present a method to remove these effects. We also present a method to remove the interference patterns appearing in the images obtained with longer wavelength filters and investigate the spatial variation of the point spread function.

Chaebol and Earnings Management (대규모기업집단의 차별적 이익조정 행태)

  • Lim, Hyoung-Joo
    • The Journal of the Korea Contents Association
    • /
    • v.12 no.12
    • /
    • pp.385-394
    • /
    • 2012
  • This study investigates whether earnings management behavior of chaebol firms differ from that of non-chaebol firms. The ownership structure of chaebol firms is characterized by the dominance of one largest shareholder and his family members who typically participate in the management of the firm directly or indirectly and influence most of the important management decision. This study adopts the random effect model and the hausman and talyor model, using a panel of 5092 firm-year over a period from 1991 to 2010 to control for potential heterogeneity and endogeneity that may cause sever bias. This study finds that there is no difference in accrual based earnings management level between chaebol firms and non-chaebol firms. However, chaebol firms appeared to engage less real earnings management that is known to negatively affect future earnings and share prices. The results are consistent when controlling for potential heterogeneity and endogeneity in the hausman and taylor model. The results may be of interest to various stakeholders, policy makers, standard setters and academic researchers.

MTHFR C677T Polymorphism and Ovarian Cancer Risk: A Meta-analysis

  • Ding, Xiao-Ping;Feng, Li;Ma, Li
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.13 no.8
    • /
    • pp.3937-3942
    • /
    • 2012
  • Background: Many studies have investigated possible association between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and ovarian cancer risk, but the impact is still unclear owing to the obvious inconsistencies. This study was performed to quantify the strength of the association with a metaanalysis. Methods: We searched the PubMed, Embase, and CNKI databases for studies relating the association between MTHFR C677T polymorphism and ovarian cancer risk and estimated summary odds ratios (ORs) with confidence intervals (CIs) for assessment. Results: Finally, eight studies with a total of 3,379 ovarian cancer cases and 4,078 controls were included into this meta-analysis. Overall the showed that MTHFR C677T polymorphism was not associated with ovarian cancer risk under all genetic models ($OR_{T\;versus\;C}$ = 1.03, 95%CI 0.90-1.18; $OR_{TT\;versus\;CC}$ = 1.08, 95%CI 0.79-1.47; $OR_{TT\;versus\;TC+CC}$ = 1.05, 95%CI 0.80-1.37; $OR_{TT+TC\;versus\;CC}$ = 1.05, 95%CI 0.86-1.21). Meta-analyses of studies with confirmation of HWE also showed no significant association. Subgroup analyses by ethnicity showed there was no significant association in the Caucasians but MTHFR C677T polymorphic variant T contributed to increased risk of ovarian cancer in East Asians. No evidence of publication bias was observed. Conclusion: Meta-analyses of available data show that MTHFR C677T polymorphism is not associated with ovarian cancer risk in Caucasians, but the MTHFR polymorphic variant T may contribute to increased risk in East Asians.

Thereshold Switching into Conductance Quantized Sttes in V/vamorphous- $V_{2}$ $O_{5}$/V Thin Film Devices (V/비정질- $V_{2}$ $O_{5}$ /lV 박막소자에서의 양자화된 컨덕턴스 상태로의 문턱 스위칭)

  • 윤의중
    • Journal of the Korean Institute of Telematics and Electronics D
    • /
    • v.34D no.12
    • /
    • pp.89-100
    • /
    • 1997
  • This paper investigated a new type of low voltage threshold switch (LVTS). As distinguished from the many other types of electronic threshold switches, the LvTS is ; voltage controlled, occurs at low voltages ($V_{2}$ $O_{5}$lV devices. The average low threshold voltage < $V_{LVT}$>=218 mV (standard deviation =24mV~kT/q, where T=300K), and was independent of the device area (x100) and amorphous oxide occurred in an ~22.angs. thick interphase of the V/amorphous- $V_{2}$ $O_{5}$ contacts. At $V_{LVT}$ there was a transition from an initially low conductance (OFF) state into a succession of quantized states of higher conductance (ON). The OFF state was spatically homogeneous and dominated by tunneling into the interphase. The ON state conductances were consistent with the quantized conductances of ballistic transport through a one dimensional, quantum point contact. The temeprature dependence of $V_{LVT}$, and fit of the material parameters (dielectric function, barrier energy, conductivity) to the data, showed that transport in the OFF and ON states occurred in an interphase with the characteristics of, respectively, semiconducting and metallic V $O_{2}$. The experimental results suggest that the LVTS is likely to be observed in interphases produced by a critical event associated with an inelastic transfer of energy.rgy.y.rgy.

  • PDF

Real-time controlled deposition of anti-reflection and high-reflection coatings for semiconductor laser (반도체 레이저 단면의 실시간 무반사 및 고반사 코팅)

  • 김효상;박흥진;황보창권;김부균;김형문;주흥로
    • Korean Journal of Optics and Photonics
    • /
    • v.8 no.5
    • /
    • pp.395-402
    • /
    • 1997
  • We have obtained the optimum thickness of anti-reflection(AR) coating on one of facets of a $\1.55mu\textrm{m}$ InGaAsP MQW FP semiconductor laser by in-site monitoring of the light emitted from the rear facet during the film deposition on the fore facet. The optimum thickness of $SiO_x$ thin film whose refractive index is 1.85 was found to be 188 nm. The reflectivity of the coated facet was calculated by the threshold current ratio of before and after AR coating, which was obtained from exprimental data, and it was about 2$\times$ $10^{-4}$. The results show that the output power is increased by 87% at bias current 60 mA, the slope efficiency is increased by 3.4 times, and the threshold current is increased by 2.64 times. By in-situ depositing of the $Si/SiO_2$ thin film HR coating on the rear facet, the output power was increased by 160% than before the AR and HR coatings, the slope efficiency was increased by 3.8 times, the threshold current was increased by 1.07 times, which is similar to the value of before AR coating. Due to the AR and HR coatings the output light power characteristics were enhanced.

  • PDF

MgO 표면을 diamond stylus로 마모시킬 때 발생되는 전자와 광자 방출에 관한 연구

  • 황도진;김종민;김명원
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 1999.07a
    • /
    • pp.198-198
    • /
    • 1999
  • 본 연구는 진공상태에서 단단한 물질로 된 diamond stylus로 단결정 MgO 표면에 마모(abrasion)가 할 때 발생되는 Photon emission(PHE), electron emission(EE), 마찰력을 시간의 함수로 동시에 측정하였다. 마모가 일어나는 동안 PHE 와 EE을 시간의 함수로 측정하면 마찰력 신호(signal)와 일치하지 않고 강한 fluctuation을 보여주고 있다. 마모를 가할 때 PHE와 EE의 signal은 wear 실험이 지속되는 동안은 force signal과 관계가 있다. 그러나 변형과 마찰력의 시간의 함수에는 관계하지 않음을 알 수 있다. 본 실험에서 사용된 실험장치는 PhE, EE, frictional force을 동시에 실할 수 있는 장치이다. 광자방출 실험은 공기 중에서도 할 수 있으나 전자방출은 진공에서 얻을 수 있으므로 1$\times$10-4pa하에서 실험하였다. 전자방출은 Channel electron multiplier(bias-100V)로 검출하였고, 광자 에너지는 Gencom photomultiplier를 사용하여 180~600nm의 photon을 측정하였다. 마모는 탐색기에 관계되는 접촉점의 움직임에 관계없이 실험하였다. 시료의 처리과정과 load속도에 따른 PhE, EE, data의 방출은 시료의 표면 상태에 따라 좌우되었다. cleaved 표면은 polished 표면보다 강한 emission을 나타내었다. 이것은 마찰이 표면 상태에 의존됨을 볼 수 있었다. 속도에 따라 emission이 증가하다가 ~0.5m/s이상에서 포화상태에 도달하였다. emission 측정은 열처리한 시료와 열처리 안한 시료를 비교하였다. 발광도(luminescence)는 주로 변형(deformation)에 의해 생겼으며, 전자 방출은 벽개(fracture)에 의해 발생됨을 알 수 있었다. 측정한 3개의 signal을 시간에 따라 분석하면 stick-slip-like 현상을 볼 수 있었다. 이것으로 보아 stick은 변형에 의해 생기고 ms 후에 벽개 현상이 발생됨을 볼 수 있다. 이러한 방출 현상은 마모시 일어나는 세라믹의 급격한 벽개 과정을 이해하는 데 많은 도움을 주었다. PhE와 EE signal은 다이아몬드 stylus로 단결정 MgO 기판에 마모를 가할 때 ms 단위로 검출 할 수 있었다. 방출과 마찰력은 표면조건, load, stylus velocity에 따라 변하였다. 마찰력, PhE, EE의 시간에 따른 분석에서 PhE는 변형 과정에 민감하며, EE는 stylus velocity에 의존하였다. 본 연구의 MgO 마찰 실험에서 표면 변화에 대한 정보를 얻을 수 있었다.

  • PDF