• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.5
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• pp.568-576
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• 2017

With an increase in the usage of LNG, there is a heightened interest about its safety aspects regarding the explosion of LNG carrier tank. The need for a cryogenic explosion-proof camera has increased. The camera has to work in cryogenic environment (below $-160^{\circ}C$) in LNG carrier. This study conducted design and heat transfer analysis of cryogenic camera to secure working time in limitation of heat source. The design with gap width of double pane windows was conducted based on simple vertical cavity model to insulate from cryogenic environment. The optimal gap width was 12.5 mm. For effective analysis considering convection within the camera, equivalent thermal conductivity method was adopted with ABAQUS. The working time of the camera predicted was over 10 h at warm-start condition. In cold-start condition, it required about 5 h of pre-warming time to work. The results of analysis were compared with the ones of the actual cryogenic test.

• Journal of the Korean Applied Science and Technology
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• v.24 no.1
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• pp.92-97
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• 2007

The present paper deals with gaseous carbon dioxide separation by a commercial adsorbent: X-type zeolite. Experimental work was carried out at an ambient condition focusing on how well meeting to the national guideline. A few types of reactor and material were examined, and practical capability was found in a granular bed type reactor with the flow of 2.5 CMM. An optimum design of reactor and adsorbent could provide the required concentration, less than 2500 ppm, for the continuous operation up to 10 hours. More work including automatic regeneration is now underworking.

• Journal of Korean Academy of Nursing Administration
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• v.18 no.1
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• pp.23-32
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• 2012

Purpose: The purpose of this study was to assess the clinical application of a bar code medication administration and blood transfusion system and to identify its effects from the aspect of patient safety and nurse satisfaction in a tertiary hospital. Methods: The system in this study was PDA with bar code reading capability and wireless networking function. The logs created during application of the system and administration error reports were analyzed. For nurses' satisfaction with the system, data were collected from 337 nurses using the instrument developed by Otieno et al. and analyzed using descriptive statistics. Results: The system application rate was 98.8%, and the main failure cases in the system application included bar code or network related factors. When the system was applied, 0.02% of errors were prevented. The nurses were satisfied with the system from the aspect of patient safety, however relatively less satisfied with the system from the aspect of work efficiency. Conclusion: The results of the study indicate the usefulness for patient safety of applying the bar code medication administration and blood transfusion system to clinical practice. However technological improvements including bar code and network communication are necessary to ensure higher work efficiency in nursing practice.

• KIEAE Journal
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• v.16 no.4
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• pp.79-86
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• 2016

Purpose: Frequently, the apartment management offices have difficulties in effective repair works due to their insufficient technological capability to operate long-term repair program. There also have been many cases of failure in executing urgent repairs mainly because the repair allowance has not accumulated enough for the repair works on time. This study aimed to determine core items in apartment maintenance in order to reduce the confusion and unnecessary efforts for the management office by suggesting simple list of repair items. Method: Core items are defined using several indicators. The degrees of necessity for repair work(NRW) are calculated combining the impacts to living, safety, and aesthetics. Then the degrees of burden of repair cost(BRC) are estimated by analyzing actual long-term repair program of three apartment complexes. Lastly the degrees of accumulation demand for repair allowance(AD) are calculated with NRW and BRC. Result: The core items and essential items are suggested for three apartment types as case studies based on the indicators of NRW, BRC, and AD. Then, the required accumulated allowance per $m^2$ was calculated to effectively implement repair works.

• Journal of Power Electronics
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• v.9 no.1
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• pp.74-84
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• 2009

The design and implementation of a high performance PID (Proportional Integral & Differential) style controller with zero-phase error tracking property is considered in this article. Unlike a ball screw driven system, the controller in a direct drive system should provide a high level of tracking performance while avoiding the problems due to the absence of the gear system. The stiff mechanical element in a direct drive system allows high precise positioning capability, but relatively high tracking ability with minimal position error is required. In this work, a feasible position controller named 'Unified PID controller' is presented. It will be shown that the function of the closed position loop can be designed into unity gain system in continuous time domain to provide minimal position error. The focus of this work is in two areas. First, easy gain tunable PID position controller without speed control loop is designed in order to construct feasible high performance drive system. Second, a simple but powerful zero phase error tracking strategy using the pre-designed function of the main control loop is presented for minimal tracking error in all operating conditions. Experimental results with a s-curve based position pattern commonly used in industrial field demonstrate the feasibility and effective performance of the approach.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1426-1427
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• 2006

Chalcogenide based phase-change memory has a high capability and potential for the next generation nonvolatile memory device. Fast writing speed, low writing voltage, high sensing margin, low power consume and long cycle of read/write repeatability are also good advantages of nonvolatile phase-change memory. We have been investigated the new material for the phase-change memory. Its composition is consists of chalcogenide $Ge_{1}Se_{1}Te_2$ material. We made this new material to solve problems of conventional phase-change memory which has disadvantage of high power consume and high writing voltage. In the present work, we are manufactured $Ge_{1}Se_{1}Te_{2}/Ge_{2}Sb_{2}Te_{5}/Ge_{1}Se_{1}Te_{2}$ and $Ge_{2}Sb_{2}Te_{5}/Ge_{1}Se_{1}Te_{2}/Ge_{2}Sb_{2}Te_{5}$ sandwich triple layer structure devices are manufactured to investigate its electrical properties. Through the present work, we are willing to ensure a potential of substitutional method to overcome a crystallization problem on PRAM device.

• Journal of Sensor Science and Technology
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• v.22 no.6
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• pp.415-420
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• 2013

Calibration capabilities for thermometer calibration by comparison method were assessed using high-precision industrial platinum resistance thermometers (IPRT). It was found in the performance assessment that out of 31 laboratories who participated, 28 laboratories resulted magnitude of En number less than 1 at every calibration points they submitted results in the range from 50 to $500^{\circ}C$. The results of about 75% of the laboratories showed the difference from the assigned values less than 1/10 of the tolerance level of the class B IPRT. This indicates that the participating calibration laboratories performed with satisfactory level that was enough to calibrate IPRTs to significant precision. The sensors used in this work were manufactured and chosen by the criteria of long-term instability less than 4 mK and hysteresis less than 8 mK in the temperature range used in this work. Furthermore, the change in the resistance of the sensors in the calibration temperature range were less than the uncertainty of the calibration, 25 mK (k=2).

• Korea-Australia Rheology Journal
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• v.17 no.4
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• pp.157-164
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• 2005

Hydrodynamic characteristic of surfactant drag-reducing flows is still not fully understood. This work investigated the temperature and diameter effect on hydrodynamic characteristic of cationic surfactant drag reducing flows in pipes. Solution of oleyl bishydroxyethyl methyl ammonium chloride (Ethoquad O/12), 900 ppm, as a cationic surfactant and sodium salicylate (NaSal), 540 ppm, as a counter-ion was tested at 12, 25, 40, and $50^{\circ}C$ in pipes with diameter of 13, 25, and 40 mm. Drag reduction effectiveness of this surfactant solution was evaluated in 25 mm pipe from 6 to $75^{\circ}C$. Rheological characteristic of this solution was measured by stress control type rheometer with cone-and-plate geometry. Scale-up laws proposed by previous investigators were used to evaluate the flow characteristic of the solution. It was found that this surfactant solution has clear DR capability until $70^{\circ}C$. Result of this work suggested that temperature has a significant influence in changing the hydrodynamic entrance length of surfactant drag reducing flows. From rheological measurement, it was found that the solution exhibits Shear Induced Structure at all temperatures with different degree of peak viscosity and critical shear rate.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05a
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• pp.471-476
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• 1996

In this study, the method to use the phase shift keying (PSK) communication technique in smart transmitter is presented. In nuclear applications. smart transmitters for various parameters are expected to improve the accuracy of measurement and to reduce the load of calibration work. The capability of communication in field level is the most important merit of the smart transmitter. The most popular method is using of digital and analog techniques simultaneously - transmitting measurements from the field at 4∼20mA while modulating the current to carry digital information in both directions over the same twisted pairs. Conventional smart transmitters use the frequency shift keying (FSK) method for digital communication. Generally, however, the FSK method has the speed limit at 1200 bps. Amount of information to transmit becomes increasing as the processing technique is improved. The PSK method is noticeable alternative for high speed digital communication, but it has non-zero DC component. In order to use the PSK method in the field transmission with smart transmitter, the method to remove the DC component is studied in this work.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.1
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• pp.147-165
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• 2021

In this work, we empirically evaluated the efficiency of the recent EfficientNetB0 model to identify and diagnose malaria parasite infections in blood smears. The dataset used was collected and classified by relevant experts from the Lister Hill National Centre for Biomedical Communications (LHNCBC). We prepared our samples with minimal image transformations as opposed to others, as we focused more on the feature extraction capability of the EfficientNetB0 baseline model. We applied transfer learning to increase the initial feature sets and reduced the training time to train our model. We then fine-tuned it to work with our proposed layers and re-trained the entire model to learn from our prepared dataset. The highest overall accuracy attained from our evaluated results was 94.70% from fifty epochs and followed by 94.68% within just ten. Additional visualization and analysis using the Gradient-weighted Class Activation Mapping (Grad-CAM) algorithm visualized how effectively our fine-tuned EfficientNetB0 detected infections better than other recent state-of-the-art DCNN models. This study, therefore, concludes that when fine-tuned, the recent EfficientNetB0 will generate highly accurate deep learning solutions for the identification of malaria parasites in blood smears without the need for stringent pre-processing, optimization, or data augmentation of images.