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Search Results: 1 - 10 of 5067 matches for " Kwang Ko "
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Origin of Human Language in an Evolutionary Context: Evolution-Progression Model  [PDF]
Kwang Hyun Ko
Advances in Anthropology (AA) , 2015, DOI: 10.4236/aa.2015.52007
Abstract: This article approaches what is considered to be a linguistic enigma with an interdisciplinary scientific approach. In this manuscript, the author analyzes the infant developmental stage, human anatomy, animal behavior studies, and anthropological changes. Furthermore, prominent theories in the field, such as the provisioning model, ADHD (attention deficit hyperactivity disorder) theory, and the metabolic hypothesis for human altriciality are considered in an evolutionary context to unravel the origin of language. First, two evolutionary adaptations in humans, bipedalism and delicate muscle movements, resulted in the lack of a need for “hyperfocus”. Second, a relatively safe and rich environment replaced “hyperfocus” with social cohesion. Third, a burgeoning social interaction ushered in natural selection, whereby child helplessness or early parturition supported exceptional self-consciousness (intelligence). The result of concentrated self-consciousness, which involved enlargement of the posterior parietal cortex (sense of self), prefrontal cortex (social cognition), and temporal lobe (language interpretation), was human language. Language was not a sudden revelation; instead, it was a gradual process and a built-in part of the evolutionary sequence. Last, this article implies how language might have begun in accordance with the prior multidisciplinary analysis.
Origins of Bipedalism
Kwang Hyun Ko
Quantitative Biology , 2015,
Abstract: The following manuscript reviews various theories of bipedalism and provides a holistic answer to human evolution. There are two questions regarding bipedalism: i) why were the earliest hominins partially bipedal? and ii) why did hominins become increasingly bipedal over time and replace their less bipedal ancestors? To answer these questions, the prominent theories in the field, such as the savanna-based theory, the postural feeding hypotheses, and the provisioning model, are collectively examined. Because biological evolution is an example of trial and error and not a simple causation, there may be multiple answers to the evolution of bipedalism. The postural feeding hypothesis (reaching for food/balancing) provides an explanation for the partial bipedalism of the earliest hominins. The savannah-based theory describes how the largely bipedal hominins that started to settle on the ground became increasingly bipedal. The provisioning model (food-gathering/monogamy) explains questions arising after the postural feeding hypothesis and before the savannah theory in an evolutionary timeline. Indeed, there are no straight lines between the theories, and multiple forces could have pushed the evolution of bipedalism at different points. Finally, this manuscript states that the arboreal hominins that possessed ambiguous traits of bipedalism were eliminated through choice and selection. Using the biological analogy of the okapi and giraffe, I explain how one of the branches (Homo) became increasingly bipedal while the other (Pan) adapted to locomotion for forest life by narrowing the anatomical/biological focus in evolution.
A Compact Beam Reconfigurable Antenna for Symmetric Beam Switching
Woong Kang;Kwang Hee Ko;Kangwook Kim
PIER , 2012, DOI: 10.2528/PIER12032005
Abstract: In this paper, two radiation pattern-reconfigurable antennas are designed to operate over DCS 1800 frequency bands. The geometry of the proposed antennas is symmetric with respect to the vertical center line. The electrical shapes of the antennas are composed of a monopole-loaded loop and an open wire. The open wire functions as either a director or reflector for the two antennas. Depending on the switching state, the antennas can select between two beam directions with no input impedance difference. The sizes of each antenna are then optimized to achieve beam switching capability using PIN diodes and FETs. The reflection coefficients and gain patterns for two bias conditions using both switches are measured and compared with the simulated results. The measured results show that the proposed antennas can clearly alternate their beam directions using the switching components.
Recent advances of miRNA involvement in hepatocellular carcinoma and cholangiocarcinoma  [PDF]
Kwang Suk Ko, Hui Peng, Hua Tang, Michele E. Cho, Jian Peng, Maria-Angeles Aller, Heping Yang
Open Journal of Internal Medicine (OJIM) , 2012, DOI: 10.4236/ojim.2012.23024
Abstract: MicroRNAs (miRNAs), which are a class of highly evolutionarily conserved non-coding RNAs, modulate gene expression and are regulated by specific genes. Several studies have shown that the expression of miRNAs is deregulated in Hepatitis C virus (HCV) & Hepatitis B virus (HBV) infection, liver cancer progression, tumor invasion and metastasis. There are a number of high-quality review articles relative to the general role of miRNA alterations in carcinogenesis and specific reviews dealing with the miRNA changes in hepatocellular carcinoma (HCC) and cholangio-carcinoma (CCA). Since primary liver cancer is predominantly comprised of HCC and intrahepatic cholangiocarcinoma (ICC), in the present review we specifically focus on recent advances of miRNAs related to tumorigenesis, invasion and metastasis of primary liver cancer, with special emphasis on their relationships to their target genes. HCV & HBV are major causes of liver disease, including acute and chronic hepatitis, liver cirrhosis, and HCC, while HCV infection is a risk factor for ICC. We also discuss the mi-RNA alterations involved in HCV & HBV infection. We briefly describe advances in molecular signaling of miRNAs in liver cancers and present insights into new therapeutic clues that target liver cancer.
Settling and dewatering characteristics of granulated methane-oxidizing bacteria
Kwang Ho Ahn,Kwang Soo Kim,Sung Won Kang,Chul Yong Um,Won Tae Lee,Kwang Baik Ko,
Kwang Ho Ahn
,Kwang Soo Kim,Sung Won Kang,Chul Yong Um,Won Tae Lee,Kwang Baik Ko

环境科学学报(英文版) , 2013,
Abstract: We evaluated the settling ability and dewaterability of granulated methane-oxidizing bacteria (GMOB) after granulation using a continuous-flow reactor. A comparative analysis on settling and dewatering characteristics due to changes in sludge retention time (SRT, 10, 15 and 20 days) during cultivation of GMOB was conducted. In assessing dewaterability, the specific resistance to filtration (SRF) of activated sludge and GMOB was found to be 8.21×1013-2.38×1014 and 4.88×1012-1.98×1013 m/kg, respectively. It was confirmed that as SRT decreased, SRF of GMOB increased. In the case of bound extracellular polymeric substance (EPS), activated sludge registered 147.5 mg/g-VSS while GMOB exhibited 171-177.2 mg/g-VSS. In the case of extracellular polymeric substance soluble EPS in effluent, activated sludge measured 62 mg/L and GMOB had 17.4-21.4 mg/L. The particle size analysis showed that mean particle diameters of GMOB were 402, 369, and 350 μupm, respectively, at SRTs of 20, 15 and 10 days. In addition, it was found that GMOB had a larger mean particle diameter and exhibited much better settleability and dewaterability than activated sludge did.
GPR-Based Landmine Detection and Identification Using Multiple Features
Kwang Hee Ko,Gyubin Jang,Kyungmi Park,Kangwook Kim
International Journal of Antennas and Propagation , 2012, DOI: 10.1155/2012/826404
Abstract: This paper presents a method to identify landmines in various burial conditions. A ground penetration radar is used to generate data set, which is then processed to reduce the ground effect and noise to obtain landmine signals. Principal components and Fourier coefficients of the landmine signals are computed, which are used as features of each landmine for detection and identification. A database is constructed based on the features of various types of landmines and the ground conditions, including the different levels of moisture and types of ground and the burial depths of the landmines. Detection and identification is performed by searching for features in the database. For a robust decision, the counting method and the Mahalanobis distance-based likelihood ratio test method are employed. Four landmines, different in size and material, are considered as examples that demonstrate the efficiency of the proposed method for detecting and identifying landmines. 1. Introduction Landmine removal is a critical problem faced by many countries around the world, and the situation can be compounded by natural disasters or land development. Therefore, it is an urgent issue to detect landmines in the ground and remove them safely. The process of landmine removal starts with the detection of landmines in the ground. For safe detection, non-touch-based detection methods are required. These methods involve the detection of landmines in the signals obtained by non-touch-based sensors, such as metal detectors and radars. Among those sensors, ground penetrating radars, or GPRs, are an attractive choice for landmine detection due to their advantages over other sensors. The GPR can be used as a stand-alone sensor or as a complementary sensor to a metal detector [1, 2]. It can detect both metal and nonmetal landmines [3]. Moreover, its weight can be made light, so that it can be installed in a hand-held system or in a vehicle-mounted system in the form of an array of multiple antenna elements [4–6]. In the landmine detection step, the key factor is to obtain unique signatures of a landmine from the signal, which are used as tags of each landmine. The signal may be, however, contaminated by noise, surface reflections, and so forth. Therefore, minimizing such influences and extracting the unique signatures for each landmine is an active research topic. Many studies show various methods of computing signatures from GPR data [7–12]. Tantum et al. [13] compare different algorithms for landmine detection. Each approach, however, utilizes one feature for detection, which may not
Multi-Feature Based Detection of Landmines Using Ground Penetrating Radar
Kyungmi Park;Suncheol Park;Kangwook Kim;Kwang Hee Ko
PIER , 2013, DOI: 10.2528/PIER12100405
Abstract: In this paper, we present a method for detecting anti-tank or anti-personnel landmines buried in the ground. A set of data generated by a ground penetrating radar is processed to remove the surface reflection and clutter, yielding signals for possible landmines. In order to detect landmines in the signals, features are computed and compared against a database, which contains those of various landmines. Three features are proposed to use; principal components from principal component analysis, Fourier coefficients and singular values from singular value decomposition method, each of which is chosen to represent each landmine uniquely. Detection is performed using Mahalanobis distance-based method. Examples show that the proposed method can effectively detect landmines in various burial condition.
Cellular stress-induced up-regulation of FMRP promotes cell survival by modulating PI3K-Akt phosphorylation cascades
Se Jeon, Jung Seo, Sung-Il Yang, Ji Choi, David Wells, Chan Shin, Kwang Ko
Journal of Biomedical Science , 2011, DOI: 10.1186/1423-0127-18-17
Abstract: Apoptotic cell death was induced by etoposide treatment on Hela cells. After we transiently modulated FMRP expression (silencing or enhancing) by using molecular biotechnological methods such as small hairpin RNA virus-induced knock down and overexpression using transfection with FMRP expression vectors, cellular viability was measured using propidium iodide staining, TUNEL staining, and FACS analysis along with the level of activation of PI3K-Akt pathway by Western blot. Expression level of FMRP and apoptotic regulator BcL-xL was analyzed by Western blot, RT-PCR and immunocytochemistry.An increased FMRP expression was measured in etoposide-treated HeLa cells, which was induced by PI3K-Akt activation. Without FMRP expression, cellular defence mechanism via PI3K-Akt-Bcl-xL was weakened and resulted in an augmented cell death by etoposide. In addition, FMRP over-expression lead to the activation of PI3K-Akt signalling pathway as well as increased FMRP and BcL-xL expression, which culminates with the increased cell survival in etoposide-treated HeLa cells.Taken together, these results suggest that FMRP expression is an essential part of cellular survival mechanisms through the modulation of PI3K, Akt, and Bcl-xL signal pathways.Fragile X syndrome (FXS) is a well known neurodevelopmental disorder caused by loss of fragile X linked mental retardation protein (FMRP) which is encoded by Fmr1 gene [1]. FXS patients typically show a wide spectrum of cognitive and behavioral problems such as attention deficit, anxiety and mood disorder, increased risk of seizures, autistic spectrum behaviors, and mental retardation [1]. FMRP is expressed in many tissues including testis, placenta, and brain [2,3] and in a variety of cell types including HeLa [4].FMRP is a RNA binding protein, which regulates translation of target mRNAs. A wide range of potential target mRNAs have been suggested, most of which have been correlated to the regulation of synaptic function as well as neuronal deve
Nanoradian angular stabilization of x-ray optical components
Stanislav Stoupin,Frank Lenkszus,Robert Laird,Kurt Goetze,Kwang-Je Kim,Yuri Shvyd'ko
Physics , 2010, DOI: 10.1063/1.3428722
Abstract: An x-ray free electron laser oscillator (XFELO) has been recently proposed [K. Kim, Y. Shvyd'ko, and S. Reiche, Phys. Rev. Lett. 100, 244802 (2008)]. Angular orientation and position in space of Bragg mirrors of the XFELO optical cavity must be continuously adjusted to compensate instabilities and maximize the output intensity. An angular stability of about 10 nrad (rms) is required [K. Kim and Y. Shvyd'ko Phys. Rev. STAB 12, 030703 (2009)]. To approach this goal, a feedback loop based on a null-detection principle was designed and used for stabilization of a high energy resolution x-ray monochromator ($\Delta E/E \simeq 4 \times 10^{-8}$, $E$ = 23.7 keV) and a high heat load monochromator. Angular stability of about 13 nrad (rms) has been demonstrated for x-ray optical elements of the monochromators.
Development of compact gas treatment system using secondary emission electron gun
Masato Watanabe,Yu Wang,Akitoshi Okino,Kwang-Cheol Ko,Eiki Hotta
Physics , 2004,
Abstract: It is well known that the non-thermal plasma processes using electrical discharge or electron beam are effective for the environmental pollutant removal. Especially, the electron beam can efficiently remove pollutant, because a lot of radicals which are useful to remove pollutant can be easily produced by high-energy electrons. We have developed a compact 100kV secondary emission electron gun to apply NOX removal. The device offers several inherent advantages such as compact in size, wide and uniform electron beam. Besides, the device offers good capability in high repetition rate pulsed operation with easy control compared with glow discharge or field emission control cathode guns. In present study, the NOX removal characteristics have been studied under the increased gun voltage, varied pulsed electron beam parameters such as current density and pulse width as well as gas flow rate. The experimental results indicate a better NOX removal efficiency comparing to other high-energy electron beam and electrical discharge processing.
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