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Freely falling observer and black hole radiation
Kim, Wontae,Son, Edwin J. World Scientific 2014 Modern Physics Letters A Vol.29 No.11
<P> We find radiation in an infalling frame and present an explicit analytic evidence of the failure of no drama condition by showing that an infalling observer finds an infinite negative energy density at the event horizon. The negative and positive energy density regions are divided by the newly defined zero-energy curve (ZEC). The evaporating black hole is surrounded by the negative energy which can also be observed in the infalling frame. </P>
Wontae Kim,Jungwon Choi,Hyejin Yoon,Jaewang Lee,Jin Hyun Jun 대한생식의학회 2021 Clinical and Experimental Reproductive Medicine Vol.48 No.2
Objective: Lipopolysaccharide (LPS) from Gram-negative bacteria causes poor uterine receptivity by inducing excessive inflammation at the maternal-fetal interface. This study aimed to investigate the detrimental effects of LPS on the attachment and outgrowth of various types of trophoblastic spheroids on endometrial epithelial cells (ECC-1 cells) in an in vitro model of implantation.Methods: Three types of spheroids with JAr, JEG-3, and JAr mixed JEG-3 (JmJ) cells were used to evaluate the effect of LPS on early implantation events. ECC-1 cells were treated with LPS to mimic endometrial infection, and the expression of inflammatory cytokines and adhesion molecules was analyzed by quantitative real-time polymerase chain reaction and western blotting. The attachment rates and outgrowth areas were evaluated in the various trophoblastic spheroids and ECC-1 cells treated with LPS.Results: LPS treatment significantly increased the mRNA expression of inflammatory cytokines (CXCL1, IL-8, and IL-33) and decreased the protein expression of adhesion molecules (ITGβ3 and ITGβ5) in ECC-1 cells. The attachment rates of JAr and JmJ spheroids on ECC-1 cells significantly decreased after treating the ECC-1 cells with 1 and 10 μg/mL LPS. In the outgrowth assay, JAr spheroids did not show any outgrowth areas. However, the outgrowth areas of JEG-3 spheroids were similar regardless of LPS treatment. LPS treatment of JmJ spheroids significantly decreased the outgrowth area after 72 hours of coincubation.Conclusion: An in vitro implantation model using novel JmJ spheroids was established, and the inhibitory effects of LPS on ECC-1 endometrial epithelial cells were confirmed in the early implantation process.
BOUND OF NONCOMMUTATIVITY PARAMETER BASED ON BLACK HOLE ENTROPY
KIM, WONTAE,LEE, DAEHO World Scientific 2010 Modern physics letters A Vol.25 No.38
<P> We study the bound of the noncommutativity parameter in the noncommutative Schwarzschild black hole which is a solution of the noncommutative ISO(3, 1) Poincaré gauge group. The statistical entropy satisfying the area law in the brick wall method yields a cutoff relation which depends on the noncommutativity parameter. Requiring both the cutoff parameter and the noncommutativity parameter to be real, the noncommutativity parameter can be shown to be bounded as Θ > 8.4 × 10<SUP>-2</SUP>lp. </P>
Vision-based nonintrusive context documentation for earthmoving productivity simulation
Kim, Hongjo,Ham, Youngjib,Kim, Wontae,Park, Somin,Kim, Hyoungkwan Elsevier 2019 AUTOMATION IN CONSTRUCTION - Vol.102 No.-
<P><B>Abstract</B></P> <P>Although video surveillance systems have shown potential for analyzing jobsite contexts, the necessity of a complex multi-camera surveillance system or workers' privacy issues remain as substantive hurdles to adopt such systems in practice. To address such issues, this study presents a non-intrusive earthmoving productivity analysis method using imaging and simulation. The site access log of dump trucks is used to infer earthmoving contexts, which is produced by analyzing videos recorded at the entrance and the exit of a construction site. An algorithm for license plate detection and recognition in an uncontrolled environment is developed to automatically produce the site access log, by leveraging video deinterlacing, a deep convolutional network, and rule-based post-processing. The experimental results show the effectiveness of the proposed method for producing the site access log. Based on the site access log, simulation-based productivity analysis is conducted to produce a daily productivity report, which can provide the basis for earthmoving resource planning. It is expected that the resulting daily productivity report promotes data-driven decision-making for earthmoving resource allocation, thereby improving potential for saving cost and time for earthworks with an updated resource allocation plan.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A nonintrusive earthmoving productivity analysis method is presented. </LI> <LI> Without complex video surveillance, the daily productivity report is produced. </LI> <LI> Integration of simulation and imaging increases the simulation result reliability. </LI> <LI> The report promotes data-driven decision-making for earthmoving resource planning. </LI> </UL> </P>
KIM, WONTAE,SON, EDWIN J. World Scientific 2008 Modern Physics Letters A Vol.23 No.15
<P> We study cosmological phase transitions from modified equations of motion by introducing two noncommutative parameters in the Poisson brackets, which describes the initial- and future-singularity-free phase transition in the soluble semiclassical dilaton gravity with a nonvanishing cosmological constant. Accelerated expansion and decelerated expansion appear alternatively, where the model contains the second accelerated expansion. The final stage of the universe approaches the flat spacetime independent of the initial state of the curvature scalar as long as the product of the two noncommutative parameters is less than one. Finally, we show that the initial-singularity-free condition is related to the second accelerated expansion of the universe. </P>
ENTROPY OF THE FRW UNIVERSE BASED ON THE GENERALIZED UNCERTAINTY PRINCIPLE
KIM, WONTAE,PARK, YOUNG-JAI,YOON, MYUNGSEOK World Scientific 2010 Modern Physics Letters A Vol.25 No.15
<P> The statistical entropy of the FRW universe described by time-dependent metric is newly calculated using the brick wall method based on the general uncertainty principle with the minimal length. We can determine the minimal length with the Planck scale to obtain the entropy proportional to the area of the cosmological apparent horizon. </P>
Anomaly analysis of Hawking radiationfrom acoustic black hole
Kim, Wontae,Shin, Hyeonjoon IOP Publishing Ltd 2007 Journal of high energy physics Vol.2007 No.7
The Hawking radiation from the three dimensional rotating acoustic black hole is considered from the viewpoint of anomaly cancellation method initiated by Robinson and Wilczek. Quantum field near the horizon is effectively described by two dimensional charged field with a charge identified as the angular momentum <I>m</I>. The fluxes of charge and energy are obtained from the anomaly cancellation condition and regularity at the horizon, and are shown to match with those of the two dimensional black body radiation at the Hawking temperature.