• Journal of the Korean GEO-environmental Society
• /
• v.4 no.2
• /
• pp.77-91
• /
• 2003

The Hoek-Brown failure criterion for rock masses developed first in 1980 is widely accepted and has been applied in a variety of rock engineering problems including slope analyses. The failure criterion was modified over the years because rock mass strength by the original failure criterion in 1980 was overestimated. The modified failure criterion, named Generalized Hoek-Brown Failure Criterion, was proposed with a new classification called the Geological Strength Index(GSI) in 1994. Generally, Hoek-Brown failure criterion is applied in numerical analyses of rock mass behaviors using equivalent Mohr-Coulomb parameters estimated by linear regression method. But these parameters estimated by this method have some inaccuracies to be applied and to be incorporated into numerical models and limit equilibrium programs. The most important issue is that this method cannot take account of non-linear characteristics of Hoek-Brown criterion, therefore, equivalent Mohr-Coulomb parameters is used as constant values regardless of field stress distribution in rock masses. In this study, the numerical analysis on rock slope stability considering non-linear characteristics of Hoek-Brown failure criterion was carried out. Futhermore, by the latest Hoek-Brown failure criterion in 2002, the revised estimating method of equivalent Mohr-Coulomb parameters was applied and rock mass damage criterion is introduced to account for the strength reduction due to stress relaxation and blast damge in slope stability.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.12
• /
• pp.5069-5073
• /
• 2015

The single nucleotide polymorphism (SNP) rs1053004 in Signal transducer and activator of transcription 3 (STAT3) was recently reported to be associated with chronic hepatitis B (CHB)-related hepatocellular carcinoma (HCC) in a Chinese cohort. This study was aimed at investigating whether the SNP might also contribute to HCC susceptibility in the Thai population. Study subjects were enrolled and divided into 3 groups including CHB-related HCC (n=211), CHB without HCC (n=233) and healthy controls (n=206). The SNP was genotyped using allelic discrimination assays based on TaqMan real-time PCR. Data analysis revealed that the distribution of different genotypes was in Hardy-Weinberg equilibrium (P>0.05). The frequencies of allele T (major allele) in HCC patients, CHB patients and healthy controls were 51.4%, 58.6% and 61.4%, respectively, whereas the frequencies of C allele (minor allele) were 48.6%, 41.4% and 38.6%. The C allele frequency was higher in HCC when compared with CHB patients (odds ratio (OR)=1.34, 95% confidence interval (CI)=1.02-1.74, P=0.032). The genotype of SNP rs1053004 (CC versus TT+TC) was significantly associated with an increased risk when compared with CHB patients (OR=1.83, 95% CI=1.13-2.99, P=0.015). In addition, we observed a similar trend of association when comparing HCC patients with healthy controls (OR=1.77, 95% CI=1.07-2.93, P=0.025) and all controls (OR=1.81, 95% CI=1.19-2.74, P=0.005). These findings suggest that the SNP rs1053004 in STAT3 might contribute to HCC susceptibility and could be used as a genetic marker for HCC in the Thai population.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.8
• /
• pp.3493-3498
• /
• 2015

Objective: To assess associations between codon 72 polymorphisms (Pro or B and Arg or b alleles) of the TP53 gene and lung cancer risk among Bangladeshis. Materials and Methods: The distribution of the BB, Bb, and bb genotypes and the frequencies of the B and b alleles were determined by PCR-RFLP method using DNA extracted from leucocytes of 50 confirmed lung cancer patients and 50 age-matched controls and the data were analysed. Results: The ratio of BB, Bb, and bb genotypes were in Hardy-Weinberg equilibrium except for the male patients (${\chi}2=4.6$). The B allele is overrepresented among all patients (OR=2.0, p=0.02) and the female patients (OR=4.1, $p{\leq}0.01$) compared to the controls. The BB/bb ratio was also higher among the patients (OR=3.0, p=0.03). The relative risk of cancer for having BB over bb genotype was 1.8 (p=0.04) but no effect was observed for the Bb genotype. The B allele was overrepresented among patients with adenocarcinomas (OR=2.4, $p{\leq}0.01$) and squamous cell carcinomas (OR=2.7, $p{\leq}0.01$) over the controls but the difference was not significant for those with small cell lung carcinomas (OR=1.1, p=0.66). The B allele was overrepresented among patients age 50 or younger (OR=2.7, $p{\leq}0.01$), but not for older patients (OR=1.7, p=0.07), and among smokers compared to the controls (OR=1.8-10.0, $p{\leq}0.01-0.03$). However, no correlation between increasing pack-years and lung cancer was observed. Conclusions: The Pro/Pro (BB) genotype and the B allele are risk factors for lung cancer among Bangladeshis, particularly for people under age 50, women and smokers.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.47 no.11
• /
• pp.753-760
• /
• 2019

Sparkjet actuator, also known as plasma synthetic jet actuator, which is a kind of active flow control actuator is considered as being high possibility for the supersonic flow control due to ejecting stronger jet compared to the other active flow control actuators. Sparkjet actuator generates high temperature and high pressure flow inside the cavity by using arc plasma and leads momentum by ejecting such flow through orifice or nozzle. In this research, numerical calculation of sparkjet actuator with respect to the location of electrodes which exists inside the cavity is conducted and the change of the performance of sparkjet actuator is suggested. As the location of electrodes goes closer to the bottom of the cavity, impulse is increased and the average pressure inside the cavity maintains higher. When the location of electrode is 25% and 75% of the entire cavity height, impulse is 2.515 μN·s and 2.057 μN·s, respectively. Each impulse is changed by about 9.92% and -10.09% compared to when the location of electrodes is 50% of the entire cavity height.

• Investigative Magnetic Resonance Imaging
• /
• v.6 no.2
• /
• pp.137-146
• /
• 2002

Purpose : This paper introduces an improved classification approach which adopts a deterministic relaxation method and an agglomerative clustering technique for the classification of MRI using neural network. The proposed approach can solve the problems of convergency to local optima and computational burden caused by a large number of input patterns when a neural network is used for image classification. Materials and methods : Application of Hopfield neural network has been solving various optimization problems. However, major problem of mapping an image classification problem into a neural network is that network is opt to converge to local optima and its convergency toward the global solution with a standard stochastic relaxation spends much time. Therefore, to avoid local solutions and to achieve fast convergency toward a global optimization, we adopt MFA to a Hopfield network during the classification. MFA replaces the stochastic nature of simulated annealing method with a set of deterministic update rules that act on the average value of the variable. By minimizing averages, it is possible to converge to an equilibrium state considerably faster than standard simulated annealing method. Moreover, the proposed agglomerative clustering algorithm which determines the underlying clusters of the image provides initial input values of Hopfield neural network. Results : The proposed approach which uses agglomerative clustering and deterministic relaxation approach resolves the problem of local optimization and achieves fast convergency toward a global optimization when a neural network is used for MRI classification. Conclusion : In this paper, we introduce a new paradigm to classify MRI using clustering analysis and deterministic relaxation for neural network to improve the classification results.

• Journal of Cadastre & Land InformatiX
• /
• v.47 no.2
• /
• pp.159-174
• /
• 2017

The long-term imbalances between supply and demand in office market can weaken urban growth since excessive supply of offices led to office market instability and excessive demand of offices weakens growth of urban industry. Recently, there have been a lot of new large-scale supplies, which increased volatility in Seoul office market. Nevertheless, new supply of Seoul office has not been fully examined. Given this, the focus of this article was on confirming the influences of profitability, replacement cost, and demand on new office supplies in Seoul. In examining those influences, another focus was on their relative influences over time. For these purposes, we analyzed quarterly data of Seoul office market between 2003 and 2015 using a vector error correction model (VECM). As a result, in terms of the influences on the current new supply, the impact of supply before the first quarter was negative, while that of office employment before the first quarter was positive. Also, that of interest rate before the second quarter was positive, while those of cap rate before the first quarter and cap rate before the second quarter were negative. Based on the findings, it is suggested that prediction models on Seoul offices need to be developed considering the influences of profitability, replacement cost, and demand on new office supplies in Seoul.

• Korean Chemical Engineering Research
• /
• v.45 no.5
• /
• pp.460-465
• /
• 2007

Endosulfan-${\alpha}$ endosulfan-${\beta}$ and endosulfan-sulfate, which are classified as pesticides, were degraded by use of UV energy and ultrasonic irradiation. The degradation residuals were analysed by gas chromatography with an electron capture detector and TOC (total oragnic carbon) analysis. The reactions were conducted in a quartz annular reactor equipped with a low pressure mercury multilamp (8Wx2) and a sonic generator. All the aqueous solutions were concentrated as 10 mg/L initially. Endosulfans were degraded each to result in 48.2% (${\alpha}$), 50.0% (${\beta}$) and 76.5% (sulfate) of removal efficiency by UV energy, and 66.9% (${\alpha}$), 55.8% (${\beta}$) and 72.7% (sulfate) by ultrasonic irradiation, respectively. In contrast to the results of the single-component solutions, degradation of the endosulfan-sulfate was greatly suppressed to result in the lowest degradation rate and removal efficiency in the three-component solutions. This finding suggests that there should be a reversible reaction with a substantially low equilibrium constant between endosulfan-${\alpha}$ or -${\beta}$ and -sulfate in the coexistence of the three endosulfans. TOC data showed the endosulfans were decomposed by 20%~40% toward complete mineralization, producing a quantity of intermediates induced by the radical reactions. We found that all the decay reactions considered in this study nicely fell into pseudo first-order rate.

• Korean Chemical Engineering Research
• /
• v.51 no.6
• /
• pp.700-708
• /
• 2013

Pyroprocessing has been developed for the purpose of resolving the current spent nuclear fuel management issue and enhancing the recycle of valuable resources. Pyroprocessing has been developed with the dry technologies which are performed under high temperature conditions excluding any aqueous processes. Pyro-processes which are based on the electrochemical principles require pretreatment processes and a voloxidation process is considered as a pretreatment step for an electrolytic reduction process. Various kinds of gas conditions are applicable to the voloxidation process and the understanding of Cs behavior during the process is of importance for the analyses of waste characteristics and heat load on the overall pyroprocessing. In this study, the changes of chemical compounds with the gas conditions were calculated by analyzing gas-solid reaction behavior based on the chemical equilibria on a Cs-Te-O system. $Cs_2TeO_3$ and $Cs_2TeO_4$ were selected after a Tpp diagram analysis and it was confirmed that they are relatively stable under oxidizing atmospheres while it was shown that Cs and Te would be removed by volatilization under reducing atmosphere at a high temperature. This work provided basic data for predicting Cs behavior during the voloxidation process at which compounds are chemically distributed as the first stage in the pyroprocessing and it is expected that the results would be used for setting up material balances and related purposes.

• Journal of the Korean Electrochemical Society
• /
• v.4 no.3
• /
• pp.118-124
• /
• 2001

The Langmuir adsorption isotherm of the over-potentially deposited hydrogen (OPD H) for the cathodic $H_2$ evolution reaction (HER) at the $poly-Au|0.5M\;H_2SO_4$ aqueous electrolyte interface has been studied using cyclic voltammetric and ac impedance techniques. The behavior of the phase shift $(0^{\circ}\leq{-\phi}\leq90^{\circ})$ for the optimum intermediate frequency corresponds well to that of the fractional surface coverage $(1\geq{\theta}\geq0)$ at the interface. The phase-shift profile $({-\phi}\;vs.\;E)$ for the optimum intermediate frequency, i.e., the phase-shift method, can be used as a new method to estimate the Langmuir adsorption isotherm $(\theta\;vs.\;E)$ of the OPD H for the cathodic HER at the interface. At the poly-$Au|0.5M\;H_2SO_4$ electrolyte interface, the equilibrium constant (K) and standard free energy $({\Delta}G_{ads})$ of the OPD H are $2.3\times10^{-6}\;and\;32.2\;kJ\;mol^{-1}$, respectively.

• Korean Journal of Food Science and Technology
• /
• v.16 no.4
• /
• pp.475-481
• /
• 1984

Estimation of the penetration rate of humectants has been considered to be important in effective control of food processing when intermediate moisture food is manufactured by the moist-infusion method. In this study, when shark (Isurus glaucus) muscle was soaked in four common humectants (sucrose, sorbitol, glycerol, and propylene glycol), the equation of their penetration rate was drawn as a function of time using high performance liquid chromatography analysis. Penetration rates increased with soaking temperatures and decreased inversely with molecular weights of humectants. The penetrated amounts for 10% humectant solution reached about equilibrium after soaking for 10 hours and for 30% humectant after soaking for about 7 hours. In consideration with the penetration rate of the sample soaked in 10% humectant and complex solution of each 10% humectant, little difference was found between them. When the sample was soaked in 10% humectant and 30% humectant, it seemed to be able to apply the following regression equation to estimate the penetrated amounts: M = a log (c.t)+ b where M = penetrated amounts; c = concentration of humectant; t= soaking time; a, b = constant and c.t should be within $10^3\;-\;4{\times}10^4$.