• Corrosion Science and Technology
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• v.4 no.6
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• pp.242-249
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• 2005

A lot of parts in FGD (Flue Gas Desulfurization) systems of fossil-fuel power plants show the environments in which are highly changeable and extremely acidic corrosive medium according to time and locations, e.g. in duct works, coolers and re-heaters etc. These conditions are formed when system materials are immersed in fluid that flows on them or when exhausted gas is condensed into thin layered acidic medium to contact materials of the system walls and roofs. These environments make troublesome corrosion and air pollution problems that are occurred from the leakage of the condensed solution. To cathodically protect the metallic structures in extremely acidic fluid, the properties of the protective coatings on the metal surface were very important, and epoxy Novolac coating was applied in this work. On the base of acid immersion tests, hot sulfuric acid decreased the hardness of the coatings and reduced greatly the content of $Na_2O$, $Al_2O_3$, and $SiO_2$ among the main components of the coating. A special kind of CP(Cathodic Protection) system has been developed and tested in a real scale of the FGD facility. Applied coating for this CP system was peeled off and cracked in some parts of the facility. However, the exposed metal surface to extremely acidic fluid by the failure of the coatings was successfully protected by the new CP system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.573-576
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• 2005

A compact linear and angular displacement measurement device was developed by combining a Michelson interferometer and an autocollimator to characterize the movement of a precision stage. A Michelson interferometer and an autocollimator are typical devices for measuring linear and angular displacement, respectively. By controlling the polarization of reflected beam from the target mirror of the interferometer, some part of light was retro-reflected to the light source and the reflected beam was used for angle measurement. The interferometer and the autocollimator use the same optic axis and the target mirror can be easily and precisely aligned orthogonal to the optic axis by monitoring the autocollimator s signal. The autocollimator was designed for angular resolution of 0.1 arcsec and dynamic range of 60 arcsec. The nonlinearity error of interferometer was minimized by trimming the gain and offset of the photodiode signals. Through the experiments, we evaluate the performance of measurement device and discuss its applications.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.3
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• pp.264-271
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• 1995

This paper presents the data parallel processing method between a PC and a micro-controller. To implement the method a dual port RAM for a real time data processing is used. In general an A/D & D/AC card is used to send or receive the data into or from the external plant and the PC does only the computation of the A/D and the D/A data because the A/D & D/AC card does not have the ability of computation. In this study, a data parallel processing method in which the PC and micro-controller own a common dual port RAM, is introduced, so that the PC can compute the A/D and D/A data and control the plant simultaneously. The PC system with a micro-controller and the common dual port RAM is designed and its effectiveness is investigated experimentally considering the performance of both the computation of data and the controlling and monitoring the external plant.

• Safety and Health at Work
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• v.10 no.2
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• pp.180-187
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• 2019

Background: There is considerable evidence that leadership influences workplace safety, but less is known about the relative importance of different leadership styles for safety. In addition, a leadership style characterized by an emphasis and a focus on promoting safety has rarely been investigated alongside other more general leadership styles. Methods: Data were collected through a survey to which 269 employees in a paper mill company responded. A regression analysis was conducted to examine the relative roles of transformational, transactional (management-by-exception active; MBEA), and safety-specific leadership for different safety behavioral outcomes (compliance behavior and safety initiative behaviors) and for minor and major injuries. Results: A safety-specific leadership contributed the most to the enhanced safety of the three different kinds of leadership. Transformational leadership did not contribute to any safety outcome over and above that of a safety-specific leadership, whereas a transactional leadership (MBEA) was associated with negative safety outcomes (fewer safety initiatives and increased minor injuries). Conclusion: The most important thing for leaders aiming at improving workplace safety is to continuously emphasize safety, both in their communication and by acting as role models. This highlights the importance for leadership training programs aiming to improve safety to actually focus on safety-promoting communication and behaviors rather than general leadership. Furthermore, an overly monitoring and controlling leadership style can be detrimental to attempts at achieving improved workplace safety.

• Mycobiology
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• v.50 no.5
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• pp.345-356
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• 2022

The fungal distribution, diversity, and load were analyzed in the geographically segregated island groundwater systems in Korea. A total of 79 fungal isolates were secured from seven islands and identified based on the internal transcribed spacer (ITS) sequences. They belonged to three phyla (Ascomycota, Basidiomycota, and Chlorophyta), five classes, sixteen orders, twenty-two families, and thirty-one genera. The dominant phylum was Ascomycota (91.1%), with most fungi belonging to the Cladosporium (21.5%), Aspergillus (15.2%), and Stachybotrys (8.9%) genera. Cladosporium showed higher dominance and diversity, being widely distributed throughout the geographically segregated groundwater systems. Based on the diversity indices, the genera richness (4.821) and diversity (2.550) were the highest in the groundwater system of the largest scale. As turbidity (0.064-0.462) increased, the overall fungal count increased and the residual chlorine (0.089-0.308) had low relevance compared with the total count and fungal diversity. Cladosporium showed normal mycelial growth in de-chlorinated sterilized samples. Overall, if turbidity increases under higher fungal diversity, bio-deterioration in groundwater-supplying facilities and public health problems could be intensified, regardless of chlorine treatment. In addition to fungal indicators and analyzing methods, physical hydrostatic treatment is necessary for monitoring and controlling fungal contamination.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.2
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• pp.166-171
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• 2015

Recently, the international standard RS-422 serial communication, which was primarily designed for the communications between micro-controllers, has been used as a communication method on the ship. However, as the NMEA (National Marine Electronics Association) 2000 standardization progresses recently, a high-speed Ethernet-based communication environment is expected to be an alternative communication method instead of the RS-422 gradually. In addition, the ship's main instrumentation equipment with versatility and convenience is implemented to control devices as monitoring and controlling tools. This paper describes an implementation of wireless ultrasonic anemometer and anemoscope data processing and logger system using PC network, where the control processing equipment such as a separate operational console, data-logger, and indicator is required for the system. For these, the related element technologies to implement ultrasonic anemometer and anemoscope data processing system are expressed as a functional modules, and the NMEA 2000 standard certified data-logger system is implemented without the separate operational console.

• The Journal of the Korean dental association
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• v.53 no.8
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• pp.530-537
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• 2015

Conceptually, the emergency is classified as an urgency and an emergency. The Urgency is not immediately life threatening, but could become so if not resolved promptly. So, it requires prompt patient care same as in the emergency situation. However, the emergency is immediately life threatening and requires immediate action, such as calling 119 and basic life support. Most medical emergencies in the dental clinic cases are urgencies. The incidence of true emergencies is approximately 1/1,000,000. Adequate managing medical urgencies are important because the chance of encountering medical emergencies in the dental clinic is high and higher these days especially because of rapidly aging Korean society. Many dentists indicate that many dentists feel difficulties to recognize and treat medical problems. This paper reviews the concept of medical emergencies and how to cope with commonly occurring urgencies in the dental clinic such as loss of consciousness, hypoglycemia, hyperventilation syndrome. The best treatment for medical urgencies and emergencies in the dental clinic is prevention. Also, it is required to make preparation for emergency situations such as CPR education for dentists and being well-acquainted with equipment and drugs for the emergency care as well as to systemic medical evaluation, patient monitoring, and sedations for controlling patient's anxiety and pain. In this paper, simple algorithms based on guidelines for common urgencies in the dental clinic are suggested. In conclusion, every dentist has competencies to do the urgency care adequately and basic life support. Also, advanced cardiac life support is strongly recommended when sedation is performed in the clinic.

• Geomechanics and Engineering
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• v.21 no.6
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• pp.551-564
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• 2020

High-stress and complex geological conditions impose great challenges to maintain excavation stability during deep underground mining. In this research, large anisotropic deformation and its management by support system at a deep underground mine in Western Australia were simulated through three-dimensional finite-difference model. The ubiquitous-joint model was used and calibrated in FLAC3D to reproduce the deformation and failure characteristics of the excavation based on the field monitoring results. After modeling verification, the roles of mining depth also the intercept angle between excavation axis and foliation orientation on the deformation and damage were studied. Based on the results, quantitative relationships between key factors and damage classifications were presented, which can be used as an engineering tool. Subsequently, the performance of support system installation sequences was simulated and compared at four different scenarios. The results show that, first surface support and then reinforcement installation can obtain a better controlling effect. Finally, the influence of bolt spacing and ring spacing were also discussed. The outcomes obtained in this research may play a meaningful reference for facing the challenges in thin-bedded or foliated ground conditions.

• The Transactions of the Korea Information Processing Society
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• v.4 no.8
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• pp.2038-2059
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• 1997

The physical attributes of a computer, such as processor speed, size and access time of memory, and I/O bandwidth, are fixed when the computer is delivered to the user. Under these conditions, the performance of a multi-process system where multiple processes share various resources can be enhanced by monitoring and controlling the relationship between the user processes and the system resources. This paper applies object oriented concept to the performance management and suggests a standard for the management. Resource managers and user processes are defined as managed object and a performance manager is defined as a managing object. A protocol between the user processes and performance manager is designed and attributes and methods of the objects are also defined. Through the standardization, the user processes and the performance manager can be developed independently and the system's performance can also be collectively managed.

• Korean Journal of Computational Design and Engineering
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• v.20 no.4
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• pp.420-430
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• 2015

Operator Training Simulators (OTSs) provide macroscopic training environment for plant operation. They are equipped with simulation systems for the emulation of remote monitoring and controlling operations. OTSs typically provide 2D block diagram-based graphic user interface (GUI) and connect to process simulation tools. However, process modeling for OTSs is a difficult task. Furthermore, conventional OTSs do not provide real plant field information since they are based on 2D human machine interface (HMI). In order to overcome the limitation of OTSs, we propose a new type of plant training system. This system has the capability required for collaborative training between operators and field workers. In addition, the system provides 3D virtual training environment such that field workers feel like they are in real plant site. For this, we designed system architecture and developed essential functions for the system. For the verification of the proposed system design, we implemented a prototype training system and performed experiments of collaborative training between one operator and two field workers with the prototype system.