Showing papers by "Korea University published in 1997"
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TL;DR: This article investigated the determinants of educational quality in a newly-constructed panel data set that includes output and input measures for a broad number of countries and found that family inputs and school resources are closely related to school outcomes, as measured by internationally comparable test scores, repetition rates, and drop-out rates.
Abstract: We investigate the determinants of educational quality in a newly-constructed panel data set that includes output and input measures for a broad number of countries The results show that family inputs and school resources are closely related to school outcomes, as measured by internationally comparable test scores, repetition rates, and drop-out rates Family characteristics, such as income and education of parents, have strong effects on student performance The findings also indicate that more school resources- especially smaller class sizes but probably also higher teacher salaries and greater school length- enhance educational outcomes
655 citations
TL;DR: This article explored the transferability of specific leader behaviors and processes across cultures by empirically testing specific hypotheses which addressed the generalizability of leadership behaviors and process across five nations in North America and Asia and provided evidence for conceptual and measurement equivalence for all six leader behaviors employed in the study.
Abstract: While the phenomenon of leadership is widely considered to be universal across cultures, the way in which it is operationalized is usually viewed as culturally specific. Conflicting viewpoints exist in the leadership literature concerning the transferability of specific leader behaviors and processes across cultures. This study explored these conflicting views for managers and professional workers by empirically testing specific hypotheses which addressed the generalizability of leadership behaviors and processes across five nations in North America and Asia. Confirmatory factor analyses provided evidence for conceptual and measurement equivalence for all six leader behaviors employed in the study. The findings showed cultural universality for three leader behaviors (supportive, contingent reward, and charismatic), and cultural specificity for the remaining three leader behaviors (directive, participative, and contingent punishment).
472 citations
TL;DR: It is shown that one of the mutations is allelic to ein2-1, an ethylene-insensitive mutation, confirming the role of ethylene signal transduction pathway in leaf senescence of Arabidopsis, and suggest that the three genes function at a common step of age-dependent and dark-inducedsenescence processes.
Abstract: Four mutants that show the delayed leaf senescence phenotype were isolated from Arabidopsis thaliana. Genetic analyses revealed that they are all monogenic recessive mutations and fall into three complementation groups, identifying three genetic loci controlling leaf senescence in Arabidopsis. Mutations in these loci cause delay in all senescence parameters examined, including chlorophyll content, photochemical efficiency of photosystem II, relative amount of the large subunit of Rubisco, and RNase and peroxidase activity. Delay of the senescence symptoms was observed during both age-dependent in planta senescence and dark-induced artificial senescence in all of the mutant plants. The results indicate that the three genes defined by the mutations are key genetic elements controlling functional leaf senescence and provide decisive genetic evidence that leaf senescence is a genetically programmed phenomenon controlled by several monogenic loci in Arabidopsis. The results further suggest that the three genes function at a common step of age-dependent and dark-induced senescence processes. It is further shown that one of the mutations is allelic to ein2-1, an ethylene-insensitive mutation, confirming the role of ethylene signal transduction pathway in leaf senescence of Arabidopsis.
344 citations
TL;DR: In this article, an inhomogeneous disorder model was proposed for a physically cross-linked polyaniline system, where ordered (crystalline) regions, described by three-dimensional metallic states, are connected through amorphous regions of polymer chains where one-dimensional disorder-induced localization is dominant.
Abstract: Charge transport properties, including temperature-dependent dc conductivity, thermoelectric power, electron paramagnetic resonance, microwave frequency dielectric constant and conductivity, and electric-field-dependent conductance of partially crystalline (``physically'' cross-linked) HCl-doped polyaniline correlated with x-ray structure studies, demonstrate that charge delocalization in physically cross-linked polyaniline systems is structurally controlled. Further, we observe a positive dielectric constant at room temperature which increases (to values $g~{10}^{4})$ with increasing percent crystallinity, the size of crystalline regions, and polymer chain alignment in the disordered regions, supporting the establishment of mesoscopic metallic regions. We propose an inhomogeneous disorder model for this system in which ordered (crystalline) regions, described by three-dimensional metallic states, are connected through amorphous regions of polymer chains where one-dimensional disorder-induced localization is dominant. We utilize the metallic box, interrupted metallic strands, and Nakhmedov's phonon-induced delocalization models to account for the temperature dependence of charge transport properties of the various partially crystalline polyanilines. Analyses for the sample and temperature-dependent electron paramagnetic resonance linewidth and thermoelectric power are presented.
240 citations
TL;DR: An easy extraction process is demonstrated by modifying several existing ones to isolate high quality intact DNAs from four fruit trees, grape, apple, pear, pear and persimmon and four species of conifer within a few hours.
Abstract: Because DNA degradation is mediated by secondary plant products such as phenolic terpenoids, the isolation of high quality DNA from plants containing a high content of polyphenolics has been a difficult problem. We demonstrate an easy extraction process by modifying several existing ones. Using this process we have found it possible to isolate DNAs from four fruit trees, grape (Vitis spp.), apple (Malus spp.), pear (Pyrus spp.) and persimmon (Diospyros spp.) and four species of conifer, Pinus densiflora, Pinus koraiensis,Taxus cuspidata and Juniperus chinensis within a few hours. Compared with the existing method, we have isolated high quality intact DNAs (260/280 = 1.8-2.0) routinely yielding 250-500 ng/microl (total 7.5-15 microg DNA from four to five tissue discs).
210 citations
TL;DR: Kim et al. as discussed by the authors explored Korean immigrant working wives' ongoing challenge to male dominance at home and to the unequal division of family work, and highlighted the interplay of wives' psychological resources, gender norms, and the social standing of being immigrant families in affecting wives' challenge to gender inequality at home.
Abstract: Based on in-depth interviews with 18 Korean immigrant working couples, this study explores Korean immigrant working wives' ongoing challenge to male dominance at home and to the unequal division of family work. A main factor in wives' being less obedient to their husbands is their psychological resources such as pride, competence, and honor, which they gain from awareness of their contribution to the family economy. Under immigrant family circumstances in which working for family survival is prioritized, wives feel that their negligence of family work, rejection of the superwoman ideal, and perceived right to demand their husbands' help with family work is legitimized. However, Confucian patriarchal beliefs lead these wives to place limits on the degree of challenge. The findings highlight the interplay of wives' psychological resources, gender norms, and the social standing of being immigrant families in affecting wives' challenge to gender inequality at home. Differences in effects among Korean immigran...
155 citations
TL;DR: Kim et al. as mentioned in this paper reviewed many types of the world's lactic acid fermented foods and discussed the beneficial effects of Lactic acid fermentation of food by focusing on two examples taken from Korean cuisine, kimchi and sikhae.
142 citations
TL;DR: This paper proposes an efficient algorithm to compute fuzzy weighted average, which turned out to be superior to the previous works by reducing the number of comparisons and arithmetic operations to O(n log n).
142 citations
TL;DR: In this article, Bcl-2 suppressed cell death of N18TG neuroglioma cells caused by various apoptotic stresses, including etoposide, staurosporine, anisomycin, and ultraviolet irradiation.
136 citations
TL;DR: In this article, the authors consider the inverse problem to the refraction problem and obtain upper and lower bounds of the size of an unknown object by comparing the Dirichlet data corresponding to the harmonic equation with the same Neumann data g satisfying some mild conditions.
Abstract: We consider the inverse problem to the refraction problem div$((1 + (k -1)\chi_D)
abla u)=0 in $\Omega$ and $\pd{u}{
u}=g$ on $\partial\Omega$. The inverse problem is to determine the size and the location of an unknown object D from the boundary measurement $\Lambda_D(g)=u|_{\bO}$. The results of this paper are twofold: stability and estimation of size of D. We first obtain upper and lower bounds of the size of D by comparing $\Lambda_D(g)$ with the Dirichlet data corresponding to the harmonic equation with the same Neumann data g. We then obtain logarithmic stability in the case of the disks. In the course of deriving the stability, we are able to compute a positive lower bound (independent of D) of the gradient of the solution u to the refraction problem with the Neumann data g satisfying some mild conditions.
135 citations
TL;DR: Structural comparisons of three SODs have revealed that Ap SOD has some stabilizing features at both the tertiary and the quaternary structural level: the Ap S OD monomer contains a large number of ion-pairs and theAp SOD tetramer has a dramatically increased buried surface area per monomer.
TL;DR: In this paper, a measurement of the proton structure function F2 and the total virtual photon-proton ( γ ∗ p ) cross-section is presented for 0.11 ≤ Q 2 ≤ 0.65 GeV2 and 2 × 10−6 ≤ x ≤ 6 × 10 −5, corresponding to a range in the γ − p c.m. energy of 100 ≤ W ≤ 230 GeV.
TL;DR: In this paper, a series of undoped and Si-doped GaN epilayers grown on sapphire (0001) with the carrier concentration of 4.0×1017−1.6×1019 cm−3 was investigated to investigate the evolution of stress relaxation and yellow luminescence by Si incorporation.
Abstract: We report a systematic study accomplished with a series of undoped and Si-doped GaN epilayers grown on sapphire (0001) with the carrier concentration of 4.0×1017−1.6×1019 cm−3 in order to investigate the evolution of stress relaxation and yellow luminescence by Si incorporation. As the Si doping becomes higher, the bound exciton peaks are gradually shifted to lower energy due to relaxation of the thermal residual stress with the linear coefficient of ΔE/Δσ∥=42 meV/GPa. The present results show that both the full width at half maximum of double-crystal x-ray diffractometry and the photoluminescence intensity ratio of the yellow luminescence to edge emission gradually increase as the Si incorporation becomes heavier. We suggest that the Si doping in GaN epilayers induces overall defects and gives rise to stress relaxation during the cool-down process, and the yellow luminescence may be originated from a complex of VGa and the Si-induced defect.
TL;DR: The results suggest strongly that SA may act as an endogenous signal responsible for activating particular components of resistance to P. capsici and the induction of pathogenesis-related proteins such as β-1,3-glucanase and chitinase.
TL;DR: In this article, a model for the real U.S. and U.K. exchange rate is estimated by Gibbs sampling and the Kalman filter is used to identify a permanent and transitory component.
Abstract: The paper estimates a model for the real U.S./U.K. exchange rate. The Kalman filter is used to identify a permanent and transitory component. We find the variance of the transitory component shifts among three states according to a Markov-switching process. The model is estimated by Gibbs sampling. The transitory component appears to be driven by temporary monetary phenomenon. The shifts of variance occur at times of historically significant monetary events. We find the permanent component is cointegrated with relative per capita income levels, as in the Balassa-Samuelson hypothesis. The data support a model that contains a transitory component driven by monetary phenomena and a permanent component driven by relative income levels.
TL;DR: In this article, the authors studied the reaction e+p → e+ X for Q2 > 5000 GeV2 with a 20.1 pb−1 data sample collected during the years 1994 to 1996.
Abstract: Using the ZEUS detector at HERA, we have studied the reaction e+p → e+
X for Q2 > 5000 GeV2 with a 20.1 pb−1 data sample collected during the years 1994 to 1996. For Q2 below 15000 GeV2, the data are in good agreement with Standard Model expectations. For Q2 > 35000 GeV2, two events are observed while 0.145 ± 0.013 events are expected. A statistical analysis of a large ensemble of simulated Standard Model experiments indicates that with probability 6.0%, an excess at least as unlikely as that observed would occur above some Q2 cut. For x > 0.55 and y > 0.25, four events are observed where 0.91+ - 0.08 events are expected. A statistical analysis of the two-dimensional distribution of the events in x and y yields a probability of 0.72% for the region x > 0.55 and y > 0.25 and a probability of 7.8% for the entire Q2 > 5000 GeV2 data sample. The observed excess above Standard Model expectations is particularly interesting because it occurs in a previously unexplored kinematic region.
TL;DR: In this article, the yield loci have been measured for cold rolled steel sheets prestrained by two-stage loading and the effects of the two stage prestrains on the subsequent yielding has been investigated.
Abstract: Yield loci have been measured for cold rolled steel sheets prestrained by two stage loading. During the first loading, the sheets have been stretched by 3 and 6% tensile strain in the rolling direction. The second loading was at angles to the rolling direction with varying amounts of tensile strain. Then a set of tensile test specimens has been prepared from each of the prestrained sheets. From tensile tests, effects of the two-stage prestrains on the subsequent yielding has been investigated. Experiments show that initial orthotropic symmetry is maintained and that the orientations of orthotropy axes change continuously throughout the prestraining process. A simple phenomenological rule for the rotation of orthotropy axes is suggested.
TL;DR: Current research directions of the QBIC project such as indexing for high-dimensional multimedia data, retrieval of gray level images, and storyboard generation suitable for video are discussed.
Abstract: QBICTM (Query By Image Content) is a set of technologies and associated software that allows a user to search, browse, and retrieve image, graphic, and video data from large on-line collections. This paper discusses current research directions of the QBIC project such as indexing for high-dimensional multimedia data, retrieval of gray level images, and storyboard generation suitable for video. It describes aspects of QBIC software including scripting tools, application interfaces, and available GUIs, and gives examples of applications and demonstration systems using it.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this paper, the authors review the direct measurements of the top quark mass Mt using the sample of events collected by the DO and CDF experiments at Fermilab and conclude that the current world average Mt = 174.3 ± 3.2 (stat.) ± 4.0 (syst.) GeV/c2.
Abstract: ▪ Abstract We review the direct measurements of the top quark mass Mt using the sample of events collected by the DO and CDF experiments at Fermilab. Measurements using events in the lepton plus jets, dilepton, and all-hadronic decay modes are reviewed, as is the combination of the results to yield the current world average Mt = 174.3 ± 3.2 (stat.) ± 4.0 (syst.) GeV/c2. We close by estimating the precision attainable with future data sets at Fermilab and the Large Hadron Collider.
TL;DR: In this article, measurements of D ∗± production in deep inelastic scattering from collisions between 27.5 GeV positrons and 820 GeV protons have been taken with the ZEUS detector at HERA.
TL;DR: The ductular-like oval cells are precursors of dysplastic ductular cells that give rise to cholangiocarcinomas after dimethylnitrosamine treatment and are concluded to be bipolar progenitor cells for hepatocytes and biliary cells.
TL;DR: In this article, the authors demonstrate that the important part of exploring the proper functional form of the hedonic price model would include investigating a dissimilar and unique hedonistic price structure when the price model is applied to different housing markets, based on the adjustment to the usual technique necessitated by the regional and cultural setting of Seoul.
Abstract: This study demonstrates that the important part of exploring the proper functional form of the hedonic price model would include investigating a dissimilar and unique hedonic price structure when the hedonic price model is applied to different housing markets. Based on the adjustment to the usual technique necessitated by the regional and cultural setting of Seoul, the criteria for significance of implicit price, root-mean-square-percentage-error, and the log-likelihood ratio test are applied to the choice of a useful functional form. We conclude that investigating the structure of a local housing market and choosing proper variables reflecting regional and cultural characteristics, both key parts of such a study, require significant adjustment to the reality of Seoul.
TL;DR: Findings indicate that although there is a great loss of dorsal root ganglion cells, there is dramatic sprouting of myelinated fibres and possibly some sprouted fibres in the dorsal roots of neuropathic pain syndromes.
TL;DR: Evidence is presented to demonstrate an involvement of this biological methylation in the integrity and maintenance of myelin.
TL;DR: The results showed that the conventional set-up value for heel velocity is valid for dry floors but is too low on oily floors because faster transfer of body weight was seen owing to decreased stride length.
Abstract: A study was conducted to provide set-up values of an important biomechanical parameter, heel velocity, for slip resistance testers. Four different floor surfaces (with or without oil contaminant) were prepared for ten subjects with each walking at a fixed velocity while carrying five different loads. Stride lengths were also measured to find whether a significant difference existed between a carrying method typically used in industry (two-handed carrying of a load in a tote box held directly in front of the body) and previously used load carrying techniques (backpack and front-back pack systems). A programmable slip resistance tester was used to measure dynamic coefficient of friction with conventional set-up values for heel velocity. The results showed that the conventional set-up value for heel velocity is valid for dry floors but is too low on oily floors because faster transfer of body weight was seen owing to decreased stride length. On oily floors, heel velocities of 60 to 140cm/s would be recommend...
TL;DR: Comparisons of the activities, yields and productivities of cellulase and xylanase obtained in shake-flask, stirred-tank, bubble-column, and air-lift reactors show that better yield and productivity were shown in a bubble- column and an external-loop air- lift than in the stirred- Tank reactor.
TL;DR: Experimental results have confirmed that the proposed recurrent neural network improves discrimination and generalization powers in the recognition of visual patterns.
Abstract: We propose a new type of recurrent neural-network architecture, in which each output unit is connected to itself and is also fully connected to other output units and all hidden units. The proposed recurrent neural network differs from Jordan's and Elman's recurrent neural networks with respect to function and architecture, because it has been originally extended from being a mere multilayer feedforward neural network, to improve discrimination and generalization powers. We also prove the convergence properties of the learning algorithm in the proposed recurrent neural network, and analyze the performance of the proposed recurrent neural network by performing recognition experiments with the totally unconstrained handwritten numeric database of Concordia University, Montreal, Canada. Experimental results have confirmed that the proposed recurrent neural network improves discrimination and generalization powers in the recognition of visual patterns.
TL;DR: A basic β-1,3-glucanase induced in pepper stems by mercuric chloride treatment acted synergistically with a pepper basic 32 kDa chitinase in inhibiting hyphal growth of F. capsici and P.cucumerinum, but did not show antifungal activity against the chitIn-containing fungi.
TL;DR: The results suggest that the mechanical and thermal allodynia from partial denervation of the tail are both dependent on NMDA receptors in their induction and maintenance, and do not support the notion that different pathological mechanisms underlie different modalities of neuropathic pain from partial peripheral nerve injury.
Abstract: PREVIOUS studies showed that heat-hyperalgesia and mechanical allodynia produced by chronic constrictive injury of the sciatic nerve were differentially sensitive to the NMDA receptor antagonist dextrorphan and to morphine and other opioid receptor agonists. These results support the hypothesis that different kinds of neuropathic pain symptoms are caused by different pathological mechanisms. In the present study we determined whether mechanical and thermal allodynia produced by unilateral transection of the ‘superior’ caudal trunk which innervates the tail in rats were differentially sensitive to the non-competitive NMDA receptor antagonist MK-801. Injection of MK-801 (0.3 mg/kg, i.p.) prior to nerve injury delayed the emergence of both types of allodynia; the antagonist-treated rats exhibited neither mechanical nor thermal allodynia at least for 4 days after the injury, whereas untreated control rats exhibited clear signs of allodynia from the first day after the injury. MK-801 injection on post-injury day 14, when the allodynia was near peak severity, suppressed temporarily both the mechanical and thermal allodynia. These results suggest that the mechanical and thermal allodynia from partial denervation of the tail are both dependent on NMDA receptors in their induction and maintenance. Thus, our results do not support the notion that different pathological mechanisms underlie different modalities of neuropathic pain from partial peripheral nerve injury.
TL;DR: The simultaneous degradation of the 4-CP and phenol is useful not only for enhanced cell growth but also for the bioremediation of both compounds, which are normally present in hazardous waste sites as a mixture.
Abstract: A 4-chlorophenol (4-CP)-degrading bacterium, strain CPW301, was isolated from soil and identified as Comamonas testosteroni. This strain dechlorinated and degraded 4-CP via a meta-cleavage pathway. CPW301 could also utilize phenol as a carbon and energy source without the accumulation of any metabolites via the same meta-cleavage pathway. When phenol was added as a additional substrate, CPW301 could degrade 4-CP and phenol simultaneously. The addition of phenol greatly accelerated the degradation of 4-CP due to the increased cell mass. The simultaneous degradation of the 4-CP and phenol is useful not only for enhanced cell growth but also for the bioremediation of both compounds, which are normally present in hazardous waste sites as a mixture.