• Journal of Sensor Science and Technology
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• v.7 no.3
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• pp.171-178
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• 1998

Silicon piezoresistive absolute pressure sensor for gas leakage alarm system was developed. This sensor must operate normally in the range of $0{\sim}600\;mmH_{2}O$ pressure, and $0{\sim}100^{\circ}C$ temperature. To make the most of this sensor for gas leakage alarm system, gas must not leak from the sensor itself when the diaphragm of the sensor fractures. Thus, the sealed diaphragm cavity was anodically bonded to pyrex 7740 glass under the condition of $10^{-4}$ torr, at $400^{\circ}C$. The sensitivity of developed sensor was $4.06{\mu}V/VmmH_{2}O$ for $600\;mmH_{2}O$ full-scale pressure range. And temperature compensation method of this sensor is to change bridge-in put-voltage linearly in proportion to the temperature variation by using diode(PXIN4001) or Al thin film resistor. By these methods the temperature effect in the range of $0{\sim}100^{\circ}C$ was compensated over 80 % for offset drift, 95 % for sensitivity.

• Korean Journal of Construction Engineering and Management
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• v.14 no.4
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• pp.84-96
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• 2013

Recently, architectural design has been changing from formal design to freeform design due to the digitalization of construction industry. Especially, the formal design has been accepted as a design trend recently and applied many times as a design concept in the architectural design competitions such as turn-key. However, various deflects such as water leak and cracks have been occurred because the traditional construction methods had been applied without any revision or adaptation of the formal construction method for the freeform building construction. Design and construction of freeform building has been developed as an new method in order to solve the problems and minimize the construction duration and cost for the freeform building. Therefore this research deduced the positive implications for developing freefrom envelope by analyzing the domestic and abroad cases and proposed the considerations during design and construction of the freeform envelope as follows. First, the freeform design should consider the constructability for the freeform envelope. Second, manufacturing technology for the two-way curvature of the unit panel should be developed. Third, exposed concrete form method should be developed for the freeform envelope of concrete. Forth, material characteristics, construction method and facility management should be considered in order to manage precipitation and keep water-proof according to the classification of the freeform envelope area.

• Journal of the Korea Safety Management & Science
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• v.17 no.4
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• pp.297-304
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• 2015

This study concerns the integrated gas sensor system of wire and wireless communication by using IoT(Internet of Things) technology. First, communication part is that it delivers the detection information, which transferred by wire or wireless communication and required control procedure based on a wireless module that receives the gas leakage information from wired or wireless detector, to administrator or user's terminal. Second, receiver part is that it shows the location and information, which received from the wired detector formed by a detecting sensor's node as linking with the communication part, and transfers these to the communication part. Third, wireless detector formed as a communication module of a detecting sensor node is that it detects gas leakage and transfers the information through wireless as a packet.Fourth, wired detector communicated with the receiver part and formed as a communication module of a detecting sensor node is that it detects gas leakage, transfers and shows the information as a packet. Fifth, administrator's terminal is that it receives gas leakage information by the communication part, transfers the signal by remote-control, and shut off a gas valve as responding the information. Sixth, database is that it is connected with the communication part; it sets and stores the default values for detecting smoke, CO., and temperature; it transfers this information to the communication part or sends a gas detecting signal to user's terminal. Seventh, user's terminal is that it receives each location's default value which stored and set at the database; it manages emergency situation as shutting off a gas valve through remote control by corresponding each location's gas leakage information, which transferred from the detector to the communication part by wireless.It is possible to process a high quality data regarding flammable or toxic gas by transferring the data, which measured by a sensor module of detector, to the communication part through wire and wireless. And, it allows a user to find the location by a smart phone where gas leaks. Eventually, it minimizes human life or property loss by having stability on gas leakage as well as corresponding each location's information quickly.

• Journal of Pharmaceutical Investigation
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• v.30 no.3
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• pp.167-172
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• 2000

The purpose of this study is to develop a transurethral liquid suppository containing prostaglandin $E_1\;(PGE_1)-loaded$ microemulsion, which undergoes a phase transition to gels at body temperature. The effects of oils, ethanol as solvent and HCl as pH-controlling agent on the physicochemical properties of liquid suppositories composed of poloxamer P 407, P 188 and carbopol was investigated. The stability of $PGE_1$ and release of $PGE_1$ from liquid suppository were evaluated. Oils such as Neobee and soybean oil significantly decreased the gelation temperature but increased the gel strength of liquid suppository due to their strongly binding with the components of liquid suppository base. However, ethanol slightly did the opposite. The pH of liquid suppositories hardly affected the gelation temperature and gel strength due to addition of very small HCl (0.005-0.01%). A liquid suppository [$PGE_1/P$ 407/P 188/carbopol/Neobee/ethanol/HCl (0.2/14/14/0.4/7/2/0.005%)], which had the gelation temperature $(34.2{\pm}0.6^{\circ}C)$ and gel strength $(31.35{\pm}4.37\;sec)$ suitable for liquid suppository system, was easily administered and not leak out from the body. About 60% of $PGE_1$ was released out within 2 h from this formulation. It was shown that the release of $PGE_1$ was proportional to the square root of time, indicating that $PGE_1$ might be released from the suppository by Fickian diffusion. It was stable at $4^{\circ}C$ for at least 2 months. The results suggest that transurethral liquid suppository containing prostaglandin $E_1-loaded$ microemulsion is thought to be a convenient, safe and effective dosage form for $PGE_1$. However, it should be further developed as a more convenient and stable dosage form for $PGE_1$.

• Journal of the Korean Institute of Gas
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• v.21 no.6
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• pp.88-95
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• 2017

The usage of toxic gas in Korea is increasing in the development of high-tech industries such as semiconductors, displays and solar panels. The recent survey of domestic toxic gas consumption indicates an increase in annual average of 12.4 percent, but it is still focused on usage, and it is negligent in safety and treating the post. In September 2012, an accident occurred in Gu-mi involving hydrofluoric acid leak demonstrates the absence of safety management. Due to the incident, the government, industry and academia have been interested in chemical substances(toxic gas), and the government-led safety management has been established and implemented, but there are still a lot of safety blind spots. The purpose of this study is to develop effective measurement methods for the destruction or removal efficiency of gaseous materials emitted from the Scrubber used in the semiconductor and display industries. Also, this study demonstrated how toxic gas facilities can be applied without error by verification test for the measurement method guideline of the destruction or removal efficiency of the green-house gas reduction facility in the semiconductor and display industries used by the National Institute of Environmental Research and the UNFCCC, and suggested the differentiated measurement methods for toxic gas reduction facilities, and the third party certification for safety facilities is needed to prevent toxic gas accidents.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.51-62
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• 1993

A computational program ［TDET］ of the particle transport equation is developed on radiation shielding problem in two-dimensional cartesian geometry based on the discrete element method. Not like the ordinary discrete ordinates method, the quadrature set of angles is not fixed but steered by the spatially dependent angular fluxes. The angular dependence of the scattering source term in the particle transport equation is described by series expansion in spherical harmonics, and the energy dependence of the particles is considered as well. Three different benchmark tests are made for verification of TDET : For the ray effect analysis on a square absorber with a flat isotropic source, the results of TDET calculation are quite well conformed to those of MORSE-CG calculation while TDET ameliorates the ray effect more effectively than S$_{N}$ calculation. In the analysis of the streaming leakage through a narrow vacuum duct in a shield, TDET shows conspicuous and remarkable results of streaming leakage through the duct as well as MORSE-CG does, and quite better than S$_{N}$ calculation. In a realistic reactor shielding situation which treats in two cases of the isotropic scattering and of linearly anisotropic scattering with two groups of energy, TDET calculations show local ray effect between neighboring meshes compared with S$_{N}$ calculations in which the ray effect extends broadly over several meshes.eshes.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.4
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• pp.95-102
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• 2016

Computer security incident such as confidential information leak and data destruction are constantly growing and it becomes threat to information in digital devices. To respond against the incident, digital forensic techniques are also developing to help digital incident investigation. With the development of digital forensic technology, a variety of forensic artifact has been developed to trace the behavior of users. Also, a diversity of forensic tool has been developed to extract information from forensic artifact. However, there is a issue that information from forensic tools has its own forms. To solve this problem, it needs to process data when it is output from forensic tools. Then it needs to compare and analyze processed data to identify how data is related each other and interpret the implications. To reach this, it calls for effective method to store and output data in the course of data processing. This paper aims to propose DFIOC (Digital Forensic Indicators Of Compromise) that is capable of transcribing a variety of forensic artifact information effectively during incident analysis and response. DFIOC, which is XML based format, provides "Evidence" to represent various forensic artifacts in the incident investigation. Furthermore, It provides "Forensic Analysis" to report forensic analysis result and also gives "Indicator" to investigate the trace of incidence quickly. By logging data into one sheet in DFIOC format for forensic analysis process, it is capable of avoiding unnecessary data processing. Lastly, since collected information is recorded in a normalized format, data input and output becomes much easier as well as it will be convenient to use for identification of collected information and analysis of data relationship.

• Journal of Korean Society of Disaster and Security
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• v.14 no.2
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• pp.13-23
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• 2021

This study intended to assess the reliability of topographic data using satellite imaging data. The topographical data using actual instrumentation data and satellite image data were established and applied to the rainfall-leak model, S-RAT, and the topographical data and outflow data were compared and analyzed. The actual measurement data were collected from the Water Resources Management Information System (WAMIS), and satellite image data were collected from MODIS observation sensors mounted on Terra satellites. The areas subject to analysis were selected for two rivers with more than 80% mountainous areas in the Han River basin and one river basin with more than 7% urban areas. According to the analysis, the difference between instrumentation data and satellite image data was up to 50% for peak floods and up to 17% for flood totals in rivers with high mountains, but up to 13% for peak floods and up to 4% for flood totals. The biggest difference in the video data is Landuse, which shows that MODIS satellite images tend to be recognized as cities up to 60% or more in urban streams compared to WAMIS instrumentation data, but MODIS satellite images are found to be less than 5% error in forest areas.

• Journal of the Korean Institute of Gas
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• v.23 no.1
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• pp.27-35
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• 2019

In order to solve the global warming and reduce greenhouse gas emissions, $CO_2$ capture technology was developed by applying oxy-fuel combustion. But there has been such a problem that its economic efficiency is low due to the high price of oxygen gases. ASU is known to be most suitable method to produce large quantity of oxygen, to reduce the oxygen production cost, the efficiency of ASU need to be improved. To improve the efficiency of ASU, exergy analysis can be used. The exergy analysis provides the information of used energy in the process, the location and size of exergy destruction. In this study, the exergy analysis was used for process developing and optimization of large scale ASU. The process simulation of ASU was conducted, the results were used to calculate the exergy. As a result, to reduce the exergy loss in the cold box of ASU, a lower operating pressure process was suggested. It was confirmed the importance of heat leak and heat loss reduction of cold box. Also, the unit process of ASU which requires thermal integration was confirmed.

• Nuclear Engineering and Technology
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• v.26 no.1
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• pp.41-53
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• 1994

A SGTR accident postulated at Kori unit 1 is simulated with Mihama unit experience, which occurred on February 1991, to evaluate the capability of plant to cope with the transient. The system design and plant conditions of Kori Unit 1 are much similar with those of Mihama Unit 2. Therefore, special concern has been given to evaluate the sequence and the resulting consequence of the postulated SGTR accident at the Kori unit 1 An analysis is peformed as realistically as possible, with following the EOP of Kori unit 1. The result indicates that the leak through tube break terminates within about forty minutes, and the Kori unit 1 may be sufficient to cope with SGTR accident with same type of sequence. However, the reconsideration may be required for the design of Kori unit 1 which disconnects non-safety AC power from off-site power on SI signal generation. It may be pointed out that the content of EOP for SGTR accident is not enough to require operator's proper judgements. An analysis of SGTR accident tested in the LSTF which simulated the SGTR accident at the Mihama Unit 2 is peformed using the RELAP5/MOD3. The results indicates that the code yields in general good agreement with the test, except the break flowrate at the early stage of the event.