• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.539-542
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• 2002

Crack sealing is a maintenance procedure that is commonly used to reduce pavement degradation. If cracks in pavements are not sealed, surface water penetration can reduce the strength of the sub-base layers, which can result in increased deflections of the pavement. Reduced strength of the sub-base also accelerates the deterioration of the surface, due to development of greater cracking and potholes. Crack sealing is performed to reduce water and debris penetration, thereby helping to maintain pavement structural capacity and limiting future degradation. The process of sealing cracks in pavements is however dangerous, costly, and labor-intensive operation. Labor turnover and training are increasing problems related to crack sealing crews, and as traffic volumes increase. Automating crack sealing can reduce labor and road user costs, improve work quality, and decrease worker exposure to roadway hazards. The main objective of this research is to develop an automated system for sealing cracks in pavement. Extension of the algorithms and tools presented in this research is also recommended for future study.

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1474-1480
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• 2013

Silicon carbide (SiC)-zirconium diboride ($ZrB_2$) composites were prepared by subjecting a 60:40 vol% mixture of ${\beta}$-SiC powder and $ZrB_2$ matrix to spark plasma sintering (SPS) in 15 $mm{\Phi}$ and 20 $mm{\Phi}$ molds. The 15 $mm{\Phi}$ and 20 $mm{\Phi}$ compacts were sintered for 60 sec at $1500^{\circ}C$ under a uniaxial pressure of 50 MPa and argon atmosphere. Similar composites were simulated using $Flux^{(R)}$ 3D computer simulation software. The current and power densities of the specimen sections of the simulated SiC-$ZrB_2$ composites were higher than those of the mold sections of the 15 $mm{\Phi}$ and 20 $mm{\Phi}$ mold simulated specimens. Toward the centers of the specimen sections, the current densities in the simulated SiC-$ZrB_2$ composites increased. The power density patterns of the specimen sections of the simulated SiC-$ZrB_2$ composites were nearly identical to their current density patterns. The current densities of the 15 $mm{\Phi}$ mold of the simulated SiC-$ZrB_2$ composites were higher than those of the 20 $mm{\Phi}$ mold in the center of the specimen section. The volume electrical resistivity of the simulated SiC-$ZrB_2$ composite was about 7.72 times lower than those of the graphite mold and the punch section. The power density, 1.4604 $GW/m^3$, of the 15 $mm{\Phi}$ mold of the simulated SiC-$ZrB_2$ composite was higher than that of the 20 $mm{\Phi}$ mold, 1.3832 $GW/m^3$. The $ZrB_2$ distributions in the 20 $mm{\Phi}$ mold in the sintered SiC-$ZrB_2$ composites were more uniform than those of the 15 $mm{\Phi}$ mold on the basis of energy-dispersive spectroscopy (EDS) mapping. The volume electrical resistivity of the 20 $mm{\Phi}$ mold of the sintered SiC-$ZrB_2$ composite, $6.17{\times}10^{-4}{\Omega}cm$, was lower than that of the 15 $mm{\Phi}$ mold, $9.37{\times}10^{-4}{\Omega}{\cdot}cm$, at room temperature.

• Journal of Preventive Medicine and Public Health
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• v.28 no.3 s.51
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• pp.623-639
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• 1995

We have never seen any method to cope basically with complicated situation and problems around medical reimbursement rates here in Korea since 1977 witnessed by the beginning of medical insurance. By the way researchers concerned are beginning to propose some kinds of innovative and detailed ideas to government these days. They are Diagnosis-related group(DRG) and Resource-based .elative value scale(RBRVS). In the light of this situation it is so encouraging that our government can come up with that and move. In case of RBRVS research we have already been reaching even to the level of reviewing and revising methodology for its further development after naive pilot study on internal medicine and general surgery last year. However there might be something different conditions between USA and Korea to apply the same Dr. Hsiao's method and it must be vital to check so called' total work approach' compared with 'intra-service work approach' before expanding to the whole medical fields. According to the' Intra-service approach', the physician's work is supposed to be divided into three sub-works by the name of intraservice work, pre, and post service work. These sub-works, again should be merged together to be the pre-postwork subset through some statistical methods of the estimation process applied by Dr. Hsiao's methodology in RBRVS development later on. But in this paper that estimation process was not taken because we could have real values for all of those surveyed items related to just one specialty, OB & GY. Instead, We used some statistical comparison procedures relevant to demographic characteristics, reliability & validity and correlation analysis with American RVU(Relative value unit) between the total work and merged total work from intraservice work approach. The unit of analysis was individual physicians of OB & GY and 300 physicians were selected for each approach through statistical sampling method based on national population of OB & GY physicians in Korea. And also with the thankful help of Advisory Committee under Korean Association of OB & GY, questionnaires were made and mailed to the subjects, two times. As a result there were not any statistically significant differences in demographic characteristics between the two approaches except for the variable 'Response time for the questionnaires', but in other sections of comparisons, response rate, representative values, reliability & validity test, correlation analysis with American RVU, all showed 'Total approach' was not only more rational and statistically meaningful than 'Intra-service approach' but also had considerable merits. But we are not absolutely sure about this paper's robustness. Because of some limitations, we'd rather like to suggest further researches should be followed. In that sense the first thing would be a research for the influence of doctor's characteristics, especially 'frequency' on the rating of work and the way to define total work more clearly.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.341-348
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• 2016

This study aimed to develop a microbial process for producing aminolevulinic acid (ALA) using crude glycerol. In the culture of ALA-producing cells (Escherichia coli/pH-hemA) in a medium containing crude glycerol, the cell density and production were 1.8-fold and 1.2-fold lower than those obtained from pure glycerol, respectively. However, the cell growth and production were improved by supplementing the medium with trehalose (30 or 100 g/l). Engineered cells (E. coli/pH-hemA/pS-otsBA) were constructed to express otsBA and their culture performance was compared with that of control cells (E. coli/pH-hemA/ pSTV28). The effects of isopropyl β-D-1-thiogalactopyranoside (IPTG) concentration and the time of induction were examined to improve the cell growth and ALA production in engineered cells cultured using crude glycerol. When 0.6 mM of IPTG was added at the beginning of the exponential growth phase, the ALA produced by cells was 2,121 mg/l, which was comparable to that from pure glycerol. The results demonstrate that otsBA expression endowed cells with the capacity to tolerate the toxicity of crude glycerol for direct use.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.3
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• pp.181-188
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• 2013

The increase of carbon dioxide ($CO_2$) emission is known as one of the major causes of global warming, and it has a strong influence on the global environment. Therefore many researchers and politicians have tried to regulate the $CO_2$ emission. In regards to the matter, the IMPACT (Inclusive Marine Pressure Assesment and Classification Technology) committee under the Japan Society of Naval Architects and Ocean Engineers (JASNAOE) has developed an inclusive environmental impact assessment index, so-called "Triple I(III)", in order to assess the environmental impact including economic factors due to the artificial development of marine. In this study, III was applied to compare between the environmental impact of $CO_2$ emitted by container vessels during their life-cycle period and economic benefit due to their operating. Furthermore, III was also applied to assess the comprehensive environmental impact for the cases with various capacities of container vessels and different sailing route. From the results, the case for shortening of the sailing route is more effective to get the advantageous assessment results of III than the case for varying the size of vessels.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.2
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• pp.201-208
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• 2011

With the increase in the number of smartphone users, precise 3D positional information is required by various applications. The positioning accuracy using civilian single-frequency pseudoranges is at the level of 10 m or so, but most applications these days are asking for a sub-meter level Therefore, instead of an absolute positioning technique, the VRS-based differential approach is applied along with the correction of the double-differenced (DD) residual errors using FKP (Flachen-Korrektur-Parameter). The VRS (Virual Reference Station) is located close to the rover, and the measurements are generated by correcting the geometrical distance to those of the master reference station. Since the unmodeled errors are generally proportional to the length of the baselines, the correction parameters are estimated by fitting a plane to the DD pseudorange errors of the CORS network. The DD positioning accuracy using 24 hours of C/A code measurements provides the RMS errors of 37 cm, 28 cm for latitudinal and longitudinal direction, respectively, and 76 cm for height. The accuracy of the horizontal components is within ${\pm}0.5m$ for about 90% of total epochs, and in particular the biases are significantly decreased to the level of 2-3 cm due to the network-based error modeling. Consequently, it is possible to consistently achieve a sub-meter level accuracy from the single-frequency pseudoranges using the VRS and double-differenced error modeling.

• Journal of Korean Library and Information Science Society
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• v.39 no.4
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• pp.51-69
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• 2008

This study tired to develop the web credibility evaluation model by calculating weighted values and sensitivities of indicators which presented on preceding researches using Analytic Hierarchy Process. "Expert Choice 2000" was used as the tool for analysing AHP. 25 experts are answered for this questionnaire who are selected by judgement sampling method, one of the non-probability sampling method. Also, sensitivity analyses was performed to graphically see how the alternatives change with respect to the importance of the indicators or sub-indicators. The main results are summarized as followings; i) importance analysis in first level factors: trust-worthiness(0,606), expertness(0.222), safety(0.173), ii) importance analysis in second level factors: trustfulness (0.519), reputation(0.087), usefulness (0.102), timeliness(0,093), competency(0.027), security(0.115), reliability(0,058). iii) some of the importance analysis in third level factors: the site provides comprehensive information that is attributed to a specific source(0.252), the site has articles that list citations and references(0.153), the site contains user opinions and reviews(0.072), etc. iv) sensitivity analyses showed that the importance of the indicators or sub-indicators are slightly changed with respect to the alternatives change.

• Nuclear Engineering and Technology
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• v.52 no.3
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• pp.469-476
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• 2020

Research reactors in-core experimental facilities are designed to provide the highest steady state flux for user's irradiation requirements. However, fuel conversion from highly enriched uranium (HEU) to low enriched uranium (LEU) driven by the ongoing effort to diminish proliferation risk, will impact reactor physics parameters. Preserving the reactor capability to produce the needed flux to perform its intended research functions, determines the conversion feasibility. This study investigates the neutron flux in the central experimental facility of two material test reactors (MTR), the IAEA generic10 MW benchmark reactor and the 22 MW s Egyptian Test and Research Reactor (ETRR-2). A 3D full core model with three uranium enrichment of 93%, 45%, and 20% was constructed utilizing the OpenMC particle transport Monte Carlo code. Neutronics calculations were performed for fresh fuel, the beginning of life cycle (BOL) and end of life cycle (EOL) for each of the three enrichments for both the IAEA 10 MW generic reactor and core 1/98 of the ETRR-2 reactor. Criticality calculations of the effective multiplication factor (K_eff) were executed for each of the twelve cases; results show a reasonable agreement with published benchmark values for both reactors. The thermal, epithermal and fast neutron fluxes were tallied across the core, utilizing the mesh tally capability of the code and are presented here. The axial flux in the central experimental facility was tallied at 1 cm intervals, for each of the cases; results for IAEA 10 MW show a maximum reduction of 14.32% in the thermal flux of LEU to that of the HEU, at EOL. The reduction of the thermal flux for fresh fuel was between 5.81% and 9.62%, with an average drop of 8.1%. At the BOL the thermal flux showed a larger reduction range of 6.92%-13.58% with an average drop of 10.73%. Furthermore, the fission reaction rate was calculated, results showed an increase in the peak fission rate of the LEU case compared to the HEU case. Results for the ETRR-2 reactor show an average increase of 62.31% in the thermal flux of LEU to that of the HEU due to the effect of spectrum hardening. The fission rate density increased with enrichment, resulting in 34% maximum increase in the HEU case compared to the LEU case at the assemblies surrounding the flux trap.

• Journal of Environmental Science International
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• v.26 no.2
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• pp.183-200
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• 2017

The classification of airflow patterns during high ozone ($O_3$) and $PM_{10}$ episodes on Jeju Island in recent years (2009-2015), as well as their correlation with meteorological conditions according to classified airflow patterns were investigated in this study. The airflow patterns for $O_3$ and $PM_{10}$ were classified into four types (Types A-D) and three types (Types E-G), respectively, using the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model and synoptic weather charts. Type A was the most dominant airflow pattern for $O_3$ episodes, being characterized by the transport of airflows from urban and industrial areas in China with the highest frequency (about 69%, with a mean of 67 ppb). With regard to the $PM_{10}$ episodes, Type E was the most dominant airflow pattern, and was mostly associated with long distance transport from Asian dust source regions along northwesterly winds, having the highest frequency (about 92%, with a mean of $136{\mu}g/m^3$). The variations in the concentration of $O_3$ and $PM_{10}$ during the study period were clarified in correlation with two pollutant and meteorological variables; for example, the high (low) $O_3$ and $PM_{10}$ concentrations with high (low) air temperature and/or wind speed and vice versa for precipitation. The contribution of long-range transport to the observed $PM_{10}$ levels in urban sites for different airflow patterns (Types E-F), if estimated in comparison to the data from the Gosan background site, was found to account for approximately 87-93% (on average) of its input. The overall results of the present study suggest that the variations in $O_3$ and $PM_{10}$ concentrations on Jeju Island are mainly influenced by the transport effect, as well as the contribution of local emissions.

• Parasites, Hosts and Diseases
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• v.54 no.6
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• pp.725-732
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• 2016

Plasmodium vivax produces numerous caveola-vesicle complex (CVC) structures beneath the membrane of infected erythrocytes. Recently, a member helical interspersed subtelomeric (PHIST) superfamily protein, $PcyPHIST/CVC-81_{95}$, was identified as CVCs-associated protein in Plasmodium cynomolgi and essential for survival of this parasite. Very little information has been documented to date about $PHIST/CVC-81_{95}$ protein in P. vivax. In this study, the recombinant $PvPHIST/CVC-81_{95}$ N and C termini were expressed, and immunoreactivity was assessed using confirmed vivax malaria patients sera by protein microarray. The subcellular localization of $PvPHIST/CVC-81_{95}$ N and C termini in blood stage parasites was also determined. The antigenicity of recombinant $PvPHIST/CVC-81_{95}$ N and C terminal proteins were analyzed by using serum samples from the Republic of Korea. The results showed that immunoreactivities to these proteins had 61% and 43% sensitivity and 96.9% and 93.8% specificity, respectively. The N terminal of $PvPHIST/CVC-81_{95}$ which contains transmembrane domain and export motif (PEXEL; RxLxE/Q/D) produced CVCs location throughout the erythrocytic-stage parasites. However, no fluorescence was detected with antibodies against C terminal fragment of $PvPHIST/CVC-81_{95}$. These results suggest that the $PvPHIST/CVC-81_{95}$ is localized on the CVCs and may be immunogenic in natural infection of P. vivax.