• Journal of the Korean Institute of Gas
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• v.2 no.1
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• pp.99-106
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• 1998

In order to investigate the impact properties of structural materials for LNG tank, instrumented Charpy impact tests were carried out at cryogenic temperatures. $9\%$ Ni steel showed a superior fracture resistance because of less degradation in toughness until 77 K. From the load-deflection curve obtained by an instrumented methods it was found that with the decrease of temperature from 173 K to 77 K, the peak load in the curve increased, but the total absorbed energy decreased. In addition, the energy absorbed during the crack growth was larger than one absorbed in the process of crack initiation. In SUS304L material, the energy absorbed in the process of the crack initiation was relatively large, but the energy absorbed in the process of crack growth was small, the behavior of absorbed energy was well agreed with the observations of the fracture surface which showed a relatively smooth fracture surface. The absorbed Charpy impact energy in the case of A5083 alloy was lower as compared with other steels, and some cracks were observed along the crack propagation direction at the fracture surface of 77 K.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.10
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• pp.629-636
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• 2016

This study presents the development of an acid resistance velocity sensor that is used for measuring velocity inside a copper sulfate plating bath. First, researchers investigated the acid resistance coating to confirm the suitability of the anti-acid sensor in a very corrosive environment. Then, researchers applied signal processing methods to reduce noise and amplify the signal. Next, researchers applied a pressure-resistive sensor with an operation amplifier (Op Amp) and low-pass filter with high impedance to match the output voltage of a commercial flowmeter. Lastly, this study compared three low-pass filters (Bessel, Butterworth and Chebyshev) to select the appropriate signal process circuit. The results show 0.0128, 0.0023, and 5.06％ of the mean square error, respectively. The Butterworth filter yielded more precise results when compared to a commercial flowmeter. The acid resistive sensor is capable of measuring velocities ranging from 2 to 6 m/s with a 2.7％ margin of error.

• Journal of Korea Spatial Information System Society
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• v.9 no.2
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• pp.55-66
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• 2007

There has been increasing concerns regarding marine mineral resources as the land energy resources has been depleting from worldwide energy crisis. Also, all the coastal countries around the world are getting into the high competition as EEZ implemented to widen each country's marine autonomy. Especially, the adoption of EEZ in UN's marine regulation agreement at the January of 1996 has aggravated conflicts among coastal countries and eventually resulted in critical agenda to determine the boundaries of EEZ among such countries. It is imperative for us to have negotiation with neighboring countries to determine the boundaries of EEZ. For the preparation of such negotiation, it is essential to have data such as mineral distribution, deep-sea geology, related agreement and marine laws, etc. Therefore, this study mainly concentrates on analyzing existing data of resources exploration and establishing standards for each type of data and manipulating data based on such standards, thereby building a database for more efficient management of EEZ data from marine resources survey. MRIS has also been developed to diversely analyze and visualize graphic and attribute data considering data usage and inter-relationship in the database. This system can provide various spatial analysis and spatial searching techniques to enable easier comparison of cost-benefit analysis and data provision of any area in EEZ thereby facilitating major policy making. In addition, the system can support sustainable management of marine resources of EEZ regions and data supply for systematic management of national marine resources. Furthermore, this will be very useful for negotiating with neighboring countries to determine EEZ boundaries to lead more favorable results.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.1
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• pp.63-70
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• 2017

In this paper, a magnetic flux leakage(MFL) based steel bar damage detection was first researched to quantify the signals from damages on the wire rope. Though many researches inspecting damages using a MFL method was proceeded until the present, the researches are at the level that diagnose whether damages are or not. This has limitation to take measures in accordance with the damage level. Thus, a MFL inspection system was modeled using a finite element analysis(FEM) program dealing with electromagnetism problems, and a steel bar specimen was adopted as a ferromagnetic object. Then, an experimental study was also carried out to verify the simulation results with a steel bar which has same damage conditions as the simulation. The MFL signals was nearly not affected by the increase of the inspection velocity, and the magnitudes of the signals are not identical according to the change of the defect width even the defects have same depth. On the basis of the analysis, the signal properties from the damages were extracted to classify the type of damages, and it could be confirmed that classification of damages using extracted signal properties is feasible.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.2 s.7
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• pp.13-22
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• 2005

The purpose of this research is how to estimate the traffic queue length in the signal intersection accurately. The current traffic queue length algorithm in COSMOS has been using the congestion diagram which comes from the speed of an average separated vehicle - using average vehicle length and the occupancy time from loop detectors. So some errors were occurred by the speed estimation method using average vehicle lengths. And Operators had been difficult to optimize some variables for measuring the traffic queue length estimation algorithm in COSMOS. Therefore the traffic queue length estimation algorithm on the basis of the relation between distances and occupancy rates from loop detectors was developed in this thesis. This thesis had the advantage of using occupancy rates which came out from loop detectors easily and no need to optimize some variables for the established algorithm in COSMOS. And the results of testing this algorithm in some sites which had installed COSMOS system showed better results than COSMOS system's results. But it was noted that further studies which carry it out in various sites and under various cases are necessary for applying to actual intersections.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.825-832
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• 2014

Previous works for detecting arrhythmia have mostly used nonlinear method such as artificial neural network, fuzzy theory, support vector machine to increase classification accuracy. Most methods require accurate detection of P-QRS-T point, higher computational cost and larger processing time. Even if some methods have the advantage in low complexity, but they generally suffer form low sensitivity. Also, it is difficult to detect PVC accurately because of the various QRS pattern by person's individual difference. Therefore it is necessary to design an efficient algorithm that classifies PVC based on QRS pattern in realtime and decreases computational cost by extracting minimal feature. In this paper, we propose PVC classification based on QRS pattern using QS interval and R wave amplitude. For this purpose, we detected R wave, RR interval, QRS pattern from noise-free ECG signal through the preprocessing method. Also, we classified PVC in realtime through QS interval and R wave amplitude. The performance of R wave detection, PVC classification is evaluated by using 9 record of MIT-BIH arrhythmia database that included over 30 PVC. The achieved scores indicate the average of 99.02% in R wave detection and the rate of 93.72% in PVC classification.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.666-668
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• 2013

Recently, the kind and number of malicious code, which operates in Operation System of smart devices, are rapidly increasing along with the fast supplement of smart devices. Especially, smart devices based on Android OS have high potential of danger to expose to malicious code as it has an easy access to system authority. When using intent, the global message system provided from Android, inter approach between applications is available, and possible to access to created data by the device. Intent provides convenience to application development in the aspect of reusability of component however, it could be appointed as a risk element in security-wise. Therefore, if intent is used in malicious purpose, it is easy to lead the condition where is weak on security. That is, it is possible to control as accessing to resources which application is carrying to operate by receiving intents as making smart device uncontrollable or consuming system resources. Especially, in case of system authority is achieved, the risks such as smart device control or personal information exposure become bigger when misusing broadcast intent through malicious code. This paper proposes a corresponding method of security vulnerability of Android intent that monitors the appearance of intent with intent pattern inspection, detects and blocks unidentified pattern intent.

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.56-61
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• 2011

Alkyl vinyl ethers such as methyl vinyl ether, propyl vinyl ether, isopropyl vinyl ether, butyl vinyl ether and isobutyl vinyl ether are usually used as industrial solvents and chemical intermediates in the chemical or pharmaceutical industry. Recently, they are popularly used as raw materials for polymer electrolyte membrane fuel cells and as cellulose dyeing assistants. However, very few investigations about process design and operation data were reported for alkyl vinyl ether compounds and there are no data for propyl vinyl ether(PVE) systems as far as we know. In this work, the isothermal VLE data are reported at 333.15 K for the ternary systems of {PVE + ethanol + benzene} by using headspace gas chromatography(HSGC) and these VLE data were correlated using Wilson, NRTL and UNIQUAC equations. The excess volumes($V^E$) and deviations in molar refractivity(${\Delta}R$) data are also reported for the sub binary systems {PVE + ethanol}, {ethanol + benzene} and {PVE + benzene} at 303.15 K. These data were correlated with Redlich-Kister equation. In addition, isoclines of $V^E$ and DR for ternary system {PVE + ethanol + benzene} were also calculated from Radojkovi equation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.6
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• pp.754-760
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• 2006

This study was conducted to examine the quality characteristics of canned kimchi prepared by minimal thermal processing. Korean cabbage kimchi was fermented at $20^{\circ}C$ for several days up to acidity $0.5{\pm}0.1%$, was packaged in cylindrical can of 115 mL and pasteurized at low temperature. Thermal processing times based on $F_{60}$ value at geometrical center of the can were determined as 23.1, 17.7 and 12.7 min at 65, 70 and $80^{\circ}C$, respectively. The quality changes of the processed kimchi were measured during storage at $20^{\circ}C$. The pH of pasteurized kimchi was higher than that of unpasteurized control. The number of lactic acid bacteria was reduced to about $10^{2}{\sim}10^{3}$ (CFU/mL). The pasteurized kimchi product showed better texture and color values compared to the control, while resulting in the lower carotenoid and ascorbic acid contents. Kimchi preparation by minimal thermal processing had a positive effect for reduction of sour taste and sour flavor in sensory quality, but gave adverse effect in acceptability because of off-taste and off-flavor.

• Journal of Korea Spatial Information System Society
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• v.12 no.1
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• pp.57-65
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• 2010

In this study, disaster damage investigation system was developed using high resolution satellite images and GIS technique to afford effective damage investigation system for widely disaster damaged area. Study area was selected in Bonghwa, Gyungsangbukdo where high magnitude of damages from torrential rain has occurred at July in 2008. GIS DB was built using 1:5,000 topographic map, cadastral map, satellite image and aerial photo to apply for investigation algorithm. Disaster damage investigation system was developed using VB NET languages, ArcObject component and MS-SQL DBMS for effective management of damage informations. The system can finding damaged area comparing pre- and post-disaster images and drawing damaged area according to the damage item unit. Extracted object was saved in Shape file format and overlayed with background GIS DB for obtaining detail information of damaged area. Disaster damage investigation system using high resolution spatial images can extract damage information rapidly and highly reliably for widely disaster areas. This system can be expected to highly contributing to enhance the disaster prevention capabilities in national level field investigation supporting and establishing recovery plan etc. This system can be utilized at the plan of disaster prevention through digital damage information and linked in national disaster information management system. Further studies are needed to better improvement in system and cover for the linkage of damage information with digital disaster registry.