• Parasites, Hosts and Diseases
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• v.54 no.3
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• pp.291-299
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• 2016

Human hydatid disease (cystic echinococcosis, CE) is a chronic parasitic infection caused by the larval stage of the cestode Echinococcus granulosus. As the disease mainly affects the liver, approximately 70% of all identified CE cases are detected in this organ. Optical molecular imaging (OMI), a noninvasive imaging technique, has never been used in vivo with the specific molecular markers of CE. Thus, we aimed to construct an in vivo fluorescent imaging mouse model of CE to locate and quantify the presence of the parasites within the liver noninvasively. Drug-treated protoscolices were monitored after marking by JC-1 dye in in vitro and in vivo studies. This work describes for the first time the successful construction of an in vivo model of E. granulosus in a small living experimental animal to achieve dynamic monitoring and observation of multiple time points of the infection course. Using this model, we quantified and analyzed labeled protoscolices based on the intensities of their red and green fluorescence. Interestingly, the ratio of red to green fluorescence intensity not only revealed the location of protoscolices but also determined the viability of the parasites in vivo and in vivo tests. The noninvasive imaging model proposed in this work will be further studied for long-term detection and observation and may potentially be widely utilized in susceptibility testing and therapeutic effect evaluation.

• International Journal of Highway Engineering
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• v.8 no.1 s.27
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• pp.1-13
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• 2006

This paper is one of the studies for developing new methodologies for improving performance of hot-mix recycled asphalt mixtures. The objective of this study is to evaluate rut-resistance characteristics of recycled asphalt mixture which was prepared by newly developed mixing method. The new mixing method provided more sufficient rejuvenation of old binder of reclaimed asphalt pavement (RAP), making homogeneous binder viscosity level in a recycled mixture. Two aggregates (gneiss and granite), two RAP contents (15% and 30%) and two contents (none and 6%) of polymer modifier (LDPE) were used. Recycled mixture was prepared with two methods; method A and method F. To examine difference of binder oxidation level by type of material within a recycled mixture, Gel-permeation chromatography(GPC) analysis was performed on the binders mixed with coarse aggregates and matrix separately. Laboratory tests were performed for evaluation of rut resistance characteristics of each recycled mixture and these includes wheel tracking (WT) test and Kim test. Rut depth and dynamic stability were obtained from WT test and deformation strength $(S_D)$ was obtained from Kim test. The results of regression analysis was shown that correlation $(R^2)$ of F mixing mixtures was higher than one of A mixing mixtures. Therefore, F mixing mixtures showed more consistent rut resistance than h mixing mixtures.

• Journal of Korean Elementary Science Education
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• v.36 no.4
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• pp.379-393
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• 2017

This study analyzed the relationship between self-directedness of science-gifted elementary students and their expression of scientific creativity in science-gifted class. A science-gifted program on the topic of Hydraulic Machine was implemented to 34 fifth-graders in the Science-Gifted Education Center of an education office in Seoul, Korea for four weeks. The self-directedness of the gifted students was divided into three types of 'General, Scientific, and Topic-Related Self-Directedness'. The products of the students' activities were assessed by using a scientific creativity assessment formula. Qualitative research, such as analysis of observations and interviews, was also conducted in order to identify characteristics that were not apparently revealed by quantitative data. The main results of this study are as follows: First, science-gifted elementary students' general self-directedness and their scientific creativity were significantly correlated (r=.373). Second, the students' scientific self-directedness and scientific creativity did not have a significant correlation (r=.294). Third, there was a positive correlation between the students' topic-related self-directedness and their expression of scientific creativity. Their self-rated scores (r=.420) for the topic-related self-directedness and the number of activity types associated with the topic had a positive correlation (r=.350). Fourth, the students were categorized into four groups according to the levels of their self-directedness and scientific creativity, and the result showed that Type HH (high self-directedness and high scientific creativity) was the most common type (15 students, 38.5%), followed by Type LL (low self-directedness and low scientific creativity) (11 students, 28.2%). Eight (20.5%) and five students (12.8 %) belonged to Type LH (low self-directedness and high scientific creativity) and Type HL (high self-directedness and low scientific creativity) respectively. Fifth, the classroom observation of the students in groups revealed that groups with more number of Type HH demonstrated better cooperation and performance. Sixth, the analysis results of the observation were almost matched to the results of the self-directedness and scientific creativity tests. The students with higher self-directedness demonstrated active class participation and good cooperative skills. The students with higher scientific creativity had a tendency to generate creative ideas more frequently in given situations. Seventh, dynamic activities were perceived as enjoyable and exciting by 76.9% of the students, but static activities that require creativity were regarded as interesting only by 23.1% of the students. Among the students who were satisfied with both the creative and static activities, Type HH accounted for the largest proportion (55.6%). In conclusion, factors such as students' interests, initiatives, and attitudes displayed through voluntary participations originated from their own daily life can predict the degree of scientific creativity associated with the topic. Also, when students were categorized into four types according to the level of self-directedness and scientific creativity, there was a tendency of active behavior in class, cooperative skill, and activity satisfaction. This suggested that we should consider self-directedness and scientific creativity in selecting the gifted, grouping them in class, and designing and executing programs for science-gifted elementary students.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.11
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• pp.1413-1420
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• 2012

To predict the dynamics behavior, running stability, etc. of a railway vehicle and to understand its physical characteristics, analytical methods are used for the testing and manufacturing of a scale model along with numerical simulations in developed countries (England, France, Japan, etc.). The test of the dynamics characteristics of full-scale models is problematic in that it is expensive and time-consuming because an entire large-scale test plant needs to be constructed, difficulties are involved in the test configuration, etc. To overcome these problems, an analytical study involving dynamics tests and computer simulations using a scaled bogie model that applies the laws of similarity was carried out. In this study, we performed stability analysis on a 1/5 small scaled bogie for parameters such as the running speed and carbody weight by using an analysis model. Furthermore, we verified the reliability by using a small-scaled derailment simulator and examined the dynamic characteristic of the 1/5 small scaled bogie.

• The Korean Journal of Physiology
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• v.9 no.2
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• pp.7-15
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• 1975

The maximum breathing capacity (MBC) and the maximum mid-expiratory flow rate (MMF) are widely used in evaluation of the ventilatory function, among various parameters of pulmonary function. The MBC volume is the amount of gas which can be exchanged per unit time during maximal voluntary hyperventilation. Performance of this test, unlike that of single breath maneuvers, is affected by the integrity of the respiratory bellows as a whole including such factors are respiratory muscle blood supply, fatigue, and progressive trapping of air. Because of this, the MBC and its relation to ventilatory requirement correlates more closely with subjective dyspnea than does any other test. The MMF is the average flow rate during expiration of the middle 50% of the vital capacity. The MMF is a measurement of a fast vital capacity related to the time required for the maneuver and the MMF relates much better to other dynamic tests of ventilatory function and to dyspnea than total vital capacity, because the MMF reflects the effective volume, or gas per unit of time. Therefore, it is important to have a prediction formula with one can compute the normal value for the subject and the compare with the measured value. However, the formulas for prediction of both MBC and MMF of the Korean children and adolescents are not yet available in the present. Hence, present investigation was attempt to derive the formulas for prediction of both MBC and MMF of the Korean children and adolescents. MBC and MMF were measured in 1,037 healthy Korean children and adolescents (1,035 male and 1,002 female) whose ages ranged from 8 to 18 years. A spirometer (9L, Collins) was used for the measurement of MBC and MMF. Both MBC and MMF were measured 3times in a standing position and the highest values were used. For measurement, the $CO_2$ absorber and sadd valve were removed from the spirometer in order to reduce the resistance in the breathing circuit and the subject was asked to breathe as fast and deeply as possible for 12 seconds in MBC and to exhale completely as fast as possible after maximum inspiration for MMF. During the measurement, investigator stood by the subject to give a constant encouragement. All the measured values were subsequently converted to values at BTPS. The formulas for MBC and MMF were derived by a manner similar to those for Baldwin et al (1949) and Im (1965) as function of age and BSA or age and height. The prediction formulas for MBC (L/min, BTPS) and MMF (L/min, BTPS) of the Korean children and adolescents as derived in this investigation are as follows: For male, MBC=[41.70+{$2.69{\times}Age(years)$}]${\times}BSA$ $(m^{2})$ MBC=[0.083+{$0.045{\times}Age(years)$}]${\times}Ht$ (cm) For female, MBC=[45.53+{$1.55{\times}Age(years)$}]${\times}BSA$ $(m^2)$ MBC=[0.189+{$0.029{\times}Age(years)$}]${\times}Ht$ (cm) For male, MMF= [0.544+{$0.066{\times}Age(years)$}]${\times}Ht$ (cm) For female, MMF=[0.416+{$0.064{\times}Age(years)$}]${\times}Ht$ (cm)

• Smart Structures and Systems
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• v.25 no.4
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• pp.487-499
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• 2020

This paper proposes a novel approach to model updating for a large-scale cable-stayed bridge based on ambient vibration tests coupled with a hybrid metaheuristic search algorithm. Vibration measurements are carried out under excitation sources of passing vehicles and wind. Based on the measured structural dynamic characteristics, a finite element (FE) model is updated. For long-span bridges, ambient vibration test (AVT) is the most effective vibration testing technique because ambient excitation is freely available, whereas a forced vibration test (FVT) requires considerable efforts to install actuators such as shakers to produce measurable responses. Particle swarm optimization (PSO) is a famous metaheuristic algorithm applied successfully in numerous fields over the last decades. However, PSO has big drawbacks that may decrease its efficiency in tackling the optimization problems. A possible drawback of PSO is premature convergence leading to low convergence level, particularly in complicated multi-peak search issues. On the other hand, PSO not only depends crucially on the quality of initial populations, but also it is impossible to improve the quality of new generations. If the positions of initial particles are far from the global best, it may be difficult to seek the best solution. To overcome the drawbacks of PSO, we propose a hybrid algorithm combining GA with an improved PSO (HGAIPSO). Two striking characteristics of HGAIPSO are briefly described as follows: (1) because of possessing crossover and mutation operators, GA is applied to generate the initial elite populations and (2) those populations are then employed to seek the best solution based on the global search capacity of IPSO that can tackle the problem of premature convergence of PSO. The results show that HGAIPSO not only identifies uncertain parameters of the considered bridge accurately, but also outperforms than PSO, improved PSO (IPSO), and a combination of GA and PSO (HGAPSO) in terms of convergence level and accuracy.

• Journal of Korea Technology Innovation Society
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• v.20 no.1
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• pp.175-204
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• 2017

The existing innovation policies and strategies mainly focused on the influencing factors for improvement of innovation outcome. However, these strategies were not always successful in driving innovative activities that make technology innovation disseminated. In this regard, innovation ecosystems approach has recently been coming to the force to establish a successful innovation strategy. The innovation ecosystems concept describes that innovation processes are evolved through collaborative networks of economic actors. In an innovation ecosystem, different organizations collaborate for technology development and its use. They interact for value co-creation by sharing mutual resources. The organizational networks are re-organized by dynamic changes of actors' interactions, which drive innovation mechanism of the networks. Recent studies on innovation ecosystems mostly have paid attention on developing theoretical frameworks to describe dynamics of an innovation ecosystem. There have hardly been empirical tests on the theoretical ecosystem models. In this vein, we investigated dynamics of an innovation ecosystem by analyzing structural characteristics of a collaborative network among organizations which are involved in the use of innovative technologies. Particularly, we examined the longitudinal changes of the interaction patterns among the organizations. This test was performed by an analysis of structural equivalence on the network dataset transformed from the organizational interactions. This result provides a guideline for an organization in developing an innovation strategy under a systemic perspective.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.1 s.12
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• pp.15-24
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• 2004

Generally, a ${\pi}$-type girder composed of two I-type girders is known to have a significant disadvantage in wind resistance design because of aerodynamic instability. A representative bridge for this girder was Tacoma Narrows Bridge. Since Tacoma Narrows Bridge had very low stiffness of the bridge structure and its cross-section shape had aerodynamic instability, the bridge collapsed after severe torsion and vibration events in 19m/s wind speed. Aerodynamic vibration can be avoided by enhancing structural stiffness and damping factor and conducting a study of cross-section shapes. This study shows the angle of attack for the four-span cable stayed bridge having ${\pi}$-type cross-section and describes the aerodynamic characteristics of the changed cross-section with aerodynamic vibration damping additions, by carrying out two-dimension vibration tests. As a result of uniform flow and turbulent flow, the study shows that because the basic ${\pi}$-type cross-section alone can have efficient wind resistant stability, there is no need to have additional aerodynamic damping equipment. Since this four 230m-main-span bridge has a large frequency and also has a big stiffness compared to other bridges containing a similar cross-section, it has aerodynamic stability under the design wind speed.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.537-543
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• 2017

Underwater glider is the long-term operating underwater robot that was developed with a purpose of continuous oceanographic observations and explorations. Torpedo-type underwater glider is not efficient from an aspect of maneuverability, because it uses a single buoyancy engine and motion controller for obtaining propulsive forces and moments. This paper introduces a ray-type underwater glider(RUG) with dual buoyancy engine, which improves the control performance of buoyancy and motion compared with torpedo-type underwater glider. Carrying out Computational Fluid Dynamics (CFD) analysis as static pitch drift test, the performance of fluid resistance for gliding motion was identified. Based on the calculated hydrodynamic coefficients, the dynamic simulation compared and analyzed the motion performance of torpedo-type and ray-type while controlling same volume of buoyancy engine. Small-sized model of RUG was developed to perform fundamental performance tests.

• Journal of Navigation and Port Research
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• v.36 no.6
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• pp.437-442
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• 2012

As of 2012, for service-area-widening and commercialization of DGPS service, the Ministry of Land, Transport and Maritime Affairs has completed a DGPS service via Terrestrial Digital Multimedia Broadcasting and doing experimental broadcasting. In this study, kinematic positioning tests were conducted based on DGPS service via T-DMB using low-cost GPS equipments in a dynamic environment. Standalone GPS, single-reference NDGPS via NTRIP, and virtual-reference DGPS via T-DMB surveys were conducted at the same time. And horizontal positioning errors were computed by comparing them with the result of high-precision positioning. As a result, when the DMB transmission interval was 3 seconds, horizontal positioning errors of standalone GPS, NTRIP-DGPS, and DMB-DGPS were 2.3m, 1.0m, and 0.7m, respectively. When the interval was 1 second, horizontal positioning errors were 2.0m, 1.2m, and 0.8m, respectively. Thus horizontal positioning accuracies improved with the DMB-DGPS compared to the traditional single-reference NDGPS.