• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.347-350
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• 2004

A space radiation analysis has been used to evaluate an ability of electronic equipment boxes or spacecrafts to endure various radiation effects, so it helps design thicknesses of structure and allocate components to meet the radiation requirements. A comparison study of space radiation dose analysis programs SPENVIS Sectoring Tool (SST) and SIGMA II is conducted through some structure cases, simple sphere shell, box and representative satellite configurations. The results and a discussion of comparison will be given. A general comparison will be shown for understanding those programs. The both programs use the same strategy, solid angle sectoring with ray-tracing method to produce an approximate dose at points in representative simple and complex models of spacecraft structures. Also the particle environment data corresponding to mission specification and radiation transport data are used as input data. But there are distinctions between them. The specification of geometry model and its input scheme, the assignment of dose point and the numbers, the prerequisite programs and ways of representing results will be discussed. SST is a web-based interactive program for sectoring analysis of complex geometries. It may be useful for a preliminary dose assessment with user-friendly interfaces and a package approach. SIGMA II is able to obtain from RSICC (Radiation Safety Information Computational Center) as a FOR-TRAN 77 source code. It may be suitable for either parametric preliminary design or detailed final design, e.g. a manned flight or radiation-sensitive component configuration design. It needs some debugs, recompiling and a tedious work to make geometrical quadric surfaces for actual spacecraft configuration, and has poor documentation. It is recommend to vist RSICC homepage and GEANT4/SSAT homepage.

• Microbiology and Biotechnology Letters
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• v.13 no.2
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• pp.119-127
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• 1985

A series of Escherichia coli mutants were exmined for ability to convert glucose and ammonium salts into phenylalanine. This enabled the biochemical changes having major. effects on phenylaianine yield, and interactions between mutations, to be identified. Changes to the common pathway of aromatic biosynthesis having a major effects include desensitization of the first enzyme (3-deoxy-D-arabinoheptulosonate synthase) to end-product inhibition, and removal of repression of enzyme synthesis. It is suggested that the 3-deoxy-D-arabino-heptulosonate synthase Phe isoenzyme has a more important effect on yield. Similarly, removal of repression and end-product inhibition on the phenylalanine terminal pathway increased yield, and changes to both common and branch pathways were synergistic. Blockage of the typrosine and tryptophan pathways had minor effects on phenylalanine yield, and a mutation affecting aramatic amino acid transport (aroP) decreased yield. With multiple-mutation strains hish specific rates of product formation (ie 0.1-0.17g phenylalanine/g cells/h) were obtained.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.156-168
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• 2017

Personal mobility (PM) can increase the mobility of individual, so that the elderly can be set as the target group for using PM because of relatively low walking ability to normal. In this study, we design PM device for elderly that can be used safely in the walking environment such as sidewalk. There are various obstacles in the walking environment, so the device must have mechanical performance to overcome all of them. In this study, we survey the status and level of obstacle factors in walking environment to determine the dynamic performance of the PM device for elderly. We check up several guidelines about walking facilities to define obstacle points for the device, establish field survey methodologies, and conduct field survey for some specific road sections. Based on the survey results, we confirm the possible problems that could arise when the dynamic performance of the device is selected based on the facility-related criteria. We also define the performance requirements for the device based on the requirements for electric wheelchair.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.255-261
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• 2005

The purpose of this paper is to analyze transport ability of Automated Guided Vehicle(AGV) and Double Stack Vehicle(DSV) at Automated Container Terminal(ACT). Usually, the main difference of AGV and DSV is capacity of container that they can transport between apron and yard block at once. AGV can carry out two 20 feet or one 40 feet maritime containers, but DSV can carry out four 20 feet or two 40 feet maritime containers. Therefore, DSV may improve more efficiency of stevedoring system of container terminal. In this paper, a simulation model using a graphics simulation system is developed to compare the proposed DSV with the current AGV at automated container terminal. The paper includes examples, performance tests and a discussion of simulation results.

• Journal of Microbiology and Biotechnology
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• v.29 no.6
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• pp.973-983
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• 2019

It is well known that iron is critical for bacterial growth and pathogenic virulence. Due to chemical similarity, $Ga^{3+}$ competes with $Fe^{3+}$ for binding to compounds that usually bind $Fe^{3+}$, thereby interfering with various essential biological reactions. In our present study, gallium(III) nitrate [$Ga(NO_3)_3$] could repress the growth of V. splendidus Vs without complete inhibition. In the presence of $Ga(NO_3)_3$, the secretion of homogentisic acid-melanin (HGA-melanin) in V. splendidus Vs cells could be increased by 4.8-fold, compared to that in the absence of $Ga(NO_3)_3$. HGA-melanin possessed the ability to reduce $Fe^{3+}$ to $Fe^{2+}$. In addition, HGA-melanin increased the mRNA levels of feoA and feoB, genes coding Fe2+ transport system proteins to 1.86- and 6.1-fold, respectively, and promoted bacterial growth to 139.2%. Similarly, the mRNA expression of feoA and feoB was upregulated 4.11-fold and 2.71-fold in the presence of $640{\mu}M$ $Ga(NO_3)_3$, respectively. In conclusion, our study suggested that although $Ga(NO_3)_3$ could interfere with the growth of V. splendidus Vs, it could also stimulate both the production of $Fe^{3+}$-reducing HGA-melanin and the expression of feoA and feoB, which facilitate $Fe^{2+}$ transport in V. splendidus Vs.

• Korean Journal of Construction Engineering and Management
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• v.20 no.5
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• pp.42-51
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• 2019

The train operation institution establishes a transportation plan based on the forecast of transport demand and the ability of train vehicles to transport, and establishes a train operation plan accordingly. The train operation plan adjusts the intervals between trains, creates a timetable (train diagram) for trains, and establishes a plan for the operation of train vehicles used for train operation. The train operation institution shall establish a crew schedule to determine and place the crew members of the trains arranged in the diagram in order to enhance the efficiency of the operation management of the trains. In this study, the authors apply the neighborhood search method that satisfies the constraints at the phase of generating the crew diagram. This suggests a methodology for efficient management of crew schedule plan. The crew diagram generated in this study compared with the existing crew diagram in accordance with the actual operating train timetable, and verified the effectiveness of the suggested method.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.297-305
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• 2021

A contractor or a main contractor is a company with full capacity to construct all project's works for the owner. A subcontractor is an organization that works with the main contractor to execute and complete work packages for the project. Selecting an effective subcontractor will help the efficiency and success of any projects in the construction industry. Therefore, this study identified subcontractor evaluation factors in Vietnam by collecting questionnaire survey data from engineers and staffs in the construction industry project environment. An exploratory factor analysis (EFA) was then performed to identify the critical factors when evaluating and selecting the subcontractor in construction projects. Moreover, when considering the impact level in terms of the average value, the research results showed that the most critical concern was the subcontractor's reputation. Furthermore, the top five factors affecting the sub-contractor evaluation and selection are (i) reputation, (ii) price, (iii) construction techniques, (iv) ability to implement projects according to commitments, and (v) subcontractor competence (the team of workers, technician staff, engineers with full capacity according to regulations). These research results provide an overall perspective that will help main contractors develop suitable subcontractors' evaluation and selection factors in their projects in the construction industry.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.1
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• pp.42-60
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• 2024

This study analyzed the characteristics of mixed traffic flows with autonomous vehicles on highway weaving sections and assessed the safety of vehicle-following pairs based on surrogate safety indicators. The intelligent driver model (IDM) was utilized to emulate the driving behavior of autonomous vehicles, and the weaving sections were divided into lengths of 300 and 600 meters for analysis within a micro-traffic simulation (VISSIM). Although significant differences were found in the average speed, density, and headway between the two sections through t-test results, no significant differences were observed when comparing the number of conflicts per indicator and the vehicle-following pair. Four safety indicators were selected for the mixed traffic evaluation based on their ability to represent risk levels similar to those perceived by drivers. The safety analysis, based on the selected four indicators, determined that autonomous vehicles following other autonomous vehicles were the safest pairing. Future research should focus on integrating these indicators into a single comprehensive index for analysis.

• Journal of the Korea Society of Computer and Information
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• v.25 no.10
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• pp.159-168
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• 2020

The purpose of this study is to confirm the general characteristics of 119 paramedics who are treating early emergency patients and to confirm the relationship between job stress and job satisfaction and to examine the effect of stress on satisfaction, a questionnaire survey was conducted on 365 paramedics in four Chungcheong provinces. The reliability of the job stress tool was Cronbach α = .87. The job satisfaction tool was Cronbach α = .84. The collected data were analyzed by SPSS WIN 18.0 program. There were differences among the sub - variables of general characteristics, but the general characteristics excluding academic ability were less correlated with job stress, and job satisfaction was higher when the subjects' age, number of dispatches and field hours were smaller. Job stress was found to be low when stress was high on first aid, dispatch, transport, medical guidance, conflicts and emergencies excluding partners. To reduce job stress of 119 paramedics, it is recommended to provide institutional support and education to improve the ability to recruit new emergency personnel and to provide emergency medical care and guidance because of diversification of dispatch methods and appropriate stress management.

• Ocean and Polar Research
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• v.42 no.3
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• pp.211-223
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• 2020

With the increasing demand for improved marine environments and safety, greater ability to minimize damages to coastal areas from harmful organisms, ship accidents, oil spills, etc. is required. In this regard, an accurate assessment and understanding of current systems is a crucial step to improve forecasting ability. In this study, we examine spatial and temporal characteristics of current systems in the adjacent seas of Jeju Island using a high-resolution regional ocean circulation model. Our model successfully captures the features of tides and tidal currents observed around Jeju Island. The tide form number calculated from the model result ranges between 0.3 and 0.45 in the adjacent seas of Jeju Island, indicating that the dominant type of tides is a combination of diurnal and semidiurnal, but predominantly semidiurnal. The spatial pattern of tidal current ellipses show that the tidal currents oscillate in a northwest-southeast direction and the rotating direction is clockwise in the adjacent seas of Jeju Island and counterclockwise in the Jeju Strait. Compared to the mean kinetic energy, the contribution of tidal current energy prevails the most parts of the region, but largely decreases in the eastern seas of Jeju Island where the Tsushima Warm Current is dominant. In addition, a Lagrangian particle-tracking experiment conducted suggests that particle trajectories in tidal currents flowing along the coast may differ substantially from the mean current direction. Thus, improving our understanding of tidal currents is essential to forecast the transport of marine pollution and harmful organisms in the adjacent seas of Jeju Island.