• Parasites, Hosts and Diseases
• /
• v.54 no.6
• /
• pp.697-702
• /
• 2016

Acanthamoeba keratitis has been increasing in recent years. Main risk factors are contact lens wear and their cleaning solutions. Most contact lens wearers use multipurpose disinfecting solutions (MPDS) for cleansing and disinfecting microorganisms because of its convenience. We determined amoebicidal effects of MPDS made in Korea and their cytotoxicity on human corneal epithelium cells. Fifteen commercial MPDS (A to O) were tested for their amoebicidal effects on Acanthamoeba castellanii trophozoites and cysts by using a most probable number (MPN) technique. Among them, 7 kinds of MPDS showed little or no amoebicidal effects for 24 hr exposure. Solutions A, B, G, H, L, and O showed positive amoebicidal effects, and solutions M and N killed almost all trophozoites and cysts after 24 hr exposure. However, 50%-N solution showed 56% cytotoxicity on human corneal epithelial cells within 4 hr exposure, and 50%-O solution also showed 62% cytotoxicity on human cells within 4 hr exposure. Solution A did not show any cytotoxicity on human cells. These results revealed that most MPDS made in Korea were ineffective to kill Acanthamoeba. The solutions having amoebicidal activity also showed high levels of cytotoxicity on human corneal epithelial cells. New formulations for improved MPDS that are amoebicidal but safe for host cells are needed to prevent Acanthamoeba keratitis.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.2
• /
• pp.496-506
• /
• 2014

In this paper the scenario based optimization of the bulbous bow of the KRISO Container Ship (KCS) is presented. The optimization of the parametrically modeled vessel is based on a statistically developed operational profile generated from noon-to-noon reports of a comparable 3600 TEU container vessel and specific development functions representing the growth of global economy during the vessels service time. In order to consider uncertainties, statistical fluctuations are added. An analysis of these data lead to a number of most probable upcoming operating conditions (OC) the vessel will stay in the future. According to their respective likeliness an objective function for the evaluation of the optimal design variant of the vessel is derived and implemented within the parametrical optimization workbench FRIENDSHIP Framework. In the following this evaluation is done with respect to vessel's calculated effective power based on the usage of potential flow code. The evaluation shows, that the usage of scenarios within the optimization process has a strong influence on the hull form.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.04a
• /
• pp.293-296
• /
• 2004

The objective of this study was to decide the designing factor for remediaton of the contaminated site. The soil and ground-water samples were analyzed and hydro- geological characteristics was assayed for the survey of pollution level. Also air-permeability test and MPN(most probable number) test were conducted for selecting the designing factor. The contaminants were mainly found in north-west part of the site and were expected to move toward the south. Ex-situ technology was expected more useful than in-situ one with the results of air-permeability test saying that air permeability was relatively low. Additional microbes were expected for remediation efficiency because residual microbes were loosely populated. The choosing of the designing factor was requisite for remediation of contaminated site.

• Journal of Environmental Health Sciences
• /
• v.33 no.5
• /
• pp.422-427
• /
• 2007

The purposes of this study were to investigate the concentration of total coliforms in sewage effluents during the period from August 2004 to October 2005. The removal efficiency range of multi-tube method and plate count method were $31.3{\sim}99.5%$ and $66.8{\sim}99.2%$, respectively. Though a correlation between the multi-tube method and the plate count method in the same sample is low, not only is an experimental procedure very simple, but the time required also is short. The seasonal correlation between methods showed more sensitive spring and summer than autumn and winter. So the study indicated plate count method can be used in rapid and reliance identification of total coliform more than the multi-tube method.

• Korean Journal of Microbiology
• /
• v.27 no.3
• /
• pp.272-278
• /
• 1989

The bacteria utilizing 3-chlorobenzoate as a sole carbon and energy source were isolated by Most-Probable-Number technique and identified in Korean coastal waters. Pseudomonas, Moraxella and Flavobacterium were dominant genera and comprised 70.2% of total isolates. Forty-four biochemical, cultural, morphological and physiological testa were performed and average linding cluster analysis was conducted from the test results. Total 92.7% of isolates were clustered into 17 groups under the 80% similarity level. The degradation of 3-chlorobenzoate was performed by many heterogeneous bacteria and the species diversity of these bacterial group offers informations of the stability of bacterial communities in relation to carbon compound cycling in coastal enviromnents.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2000.10a
• /
• pp.32-39
• /
• 2000

Probabilistic structural design optimization, which is characterized by the so-called probabilistic. constraints which introduce permissible probability of violation, is preferred to deterministic design optimization since unpredictable inherent uncertainties and randomness in structural and environmental properties are to be taken quantitatively into account by probabilistic design optimization. In this paper, the well-known reliability index based MPFP(Most Probable Failure Point) search approach and the newly introduced target performance measure based MPTP(Minimum Performance Target Point) search approach are summarized and compared. The present comparison focuses on the number of iterations required for the estimation of probabilistic constraints and a technique for improvement which removes exhaustive iterations is presented as well. A 10 bar truss problem is examined for this.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.37 no.3
• /
• pp.217-224
• /
• 2024

This paper proposes an efficient dimension reduction method (DRM) that considers the nonlinearity of the performance functions in reliability-based design optimization (RBDO). The dimension reduction method evaluates the reliability more accurately than the first-order reliability method (FORM) using integration quadrature points and weights. However, its efficiency is hindered as the number of quadrature points increases owing to the need for an additional evaluation of the performance function. In this study, we assessed the nonlinearity of the performance function in RBDO and proposed criteria for determining the number of quadrature points based on the degree of nonlinearity. This approach suggests adjusting the number of quadrature points during each iteration of the RBDO process while maintaining the accuracy of theDRM while improving the computational efficiency. The nonlinearity of the performance function was evaluated using the angle between the vectors used in the maximum probable target point (MPTP) search. Numerical tests were conducted to determine the appropriate number of quadrature points according to the degree of nonlinearity. Through a 2D numerical example, it is confirmed that the proposed method improves the efficiency while maintaining the accuracy of the dimension reduction method or Monte Carlo Simulation (MCS).

• Nuclear Engineering and Technology
• /
• v.49 no.2
• /
• pp.434-441
• /
• 2017

Containment venting is one of several essential measures to protect the integrity of the final barrier of a nuclear reactor during severe accidents, by which the uncontrollable release of fission products can be avoided. The authors seek to develop an optimization approach to venting operations, from a simulation-based perspective, using an integrated severe accident code, THALES2/KICHE. The effectiveness of the containment-venting strategies needs to be verified via numerical simulations based on various settings of the venting conditions. The number of iterations, however, needs to be controlled to avoid cumbersome computational burden of integrated codes. Bayesian optimization is an efficient global optimization approach. By using a Gaussian process regression, a surrogate model of the "black-box" code is constructed. It can be updated simultaneously whenever new simulation results are acquired. With predictions via the surrogate model, upcoming locations of the most probable optimum can be revealed. The sampling procedure is adaptive. Compared with the case of pure random searches, the number of code queries is largely reduced for the optimum finding. One typical severe accident scenario of a boiling water reactor is chosen as an example. The research demonstrates the applicability of the Bayesian optimization approach to the design and establishment of containment-venting strategies during severe accidents.

• Phonetics and Speech Sciences
• /
• v.1 no.1
• /
• pp.63-67
• /
• 2009

In this paper, in order to protect music copyrights, we propose a music identification system which is scalable to the number of pieces of registered music and robust to signal-level variations of registered music. For its implementation, we define the new concepts of 'music word' and 'music phoneme' as recognition units to construct 'music acoustic models'. Then, with these concepts, we apply the HMM-based framework used in continuous speech recognition to identify the music. Each music file is transformed to a sequence of 39-dimensional vectors. This sequence of vectors is represented as ordered states with Gaussian mixtures. These ordered states are trained using Baum-Welch re-estimation method. Music files with a suspicious copyright are also transformed to a sequence of vectors. Then, the most probable music file is identified using Viterbi algorithm through the music identification network. We implemented a music identification system for 1,000 MP3 music files and tested this system with variations in terms of MP3 bit rate and music speed rate. Our proposed music identification system demonstrates robust performance to signal variations. In addition, scalability of this system is independent of the number of registered music files, since our system is based on HMM method.

• Food Science and Biotechnology
• /
• v.14 no.3
• /
• pp.387-391
• /
• 2005

Competitive polymerase chain reaction (cPCR) was used to develop a direct enumeration method of Listeria monocytogenes in pork meat. Pork meat was artificially inoculated with L. monocytogenes and DNA was extracted using guanidine thiocyanate-phenol-chloroform and subjected to PCR amplification. Sixteen primer sets for L. monocytogenes hlyA gene were tested for sensitive detection and the DG69/DG74 primer set was selected. The detection limit achieved with this primer set was as low as 860 colony-forming units (cfu) per 0.1 g of pork meat. When the samples were cultured at $30^{\circ}C$ for 16 hr in Brain Heart Infusion (BHI) medium, even a single bacterium could be detected with this primer set by PCR. For cPCR, the hlyA gene, which features a 148 bp-deletion, was cloned in the pGEM-4Z vector. A known amount of competitor DNA which has the same primer binding sites was co-amplified with L. monocytogenes total DNA from the artificially inoculated pork meat. The cell-number determined by cPCR was approximately equal to cfu from the Most Probable Number (MPN) method. The whole procedure took only 5 hr.