• Economic and Environmental Geology
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• v.19 no.3
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• pp.225-230
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• 1986

Various interpretations on the boundary between the $Okch{\check{o}}n$ system and the Great Limestone series of the $Chos{\check{o}}n$ system, and on the geologic structure and stratigraphy of the $Okch{\check{o}}n$ system have been yielded by the previous studies, and they are still in hot debate. The present work has mainly studied on the boundary between the $Okch{\check{o}}n$ and $Chos{\check{o}}n$ systems in the south of $Jech{\check{o}}n$, and the geology in its vicinity to clarify the previous misinterpretations if any on the geologic structure and in trun stratigraphy of the area concerned. The boundary between the $Okch{\check{o}}n$ system and the Great Limestone series of the $Chos{\check{o}}n$ system has been thought to be (1) gradational relation which means two systems are the same formation, (2) unconformable relation in which the $Okch{\check{o}}n$ system overlies the $Chos{\check{o}}n$ system, (3) unconformable relation in which the $Chos{\check{o}}n$ system overlies the Okchon system indicating that the age of the $Okch{\check{o}}n$ system is Precambrian, and (4) fault contact in which the $Okch{\check{o}}n$ system of Precambrian age comes in contact with the $Chos{\check{o}}n$ system of Cambro-Ordovician age. The present study clearly found that the relationship between the two systems is a fault zone contact. Shear zone of a width of 300 to 400m is developed, and andesitic volcanics and basic dikes are intruded along the fault zone. This fault contact is exactly the north extension of the Bonghwajae fault, which was denominated long time ago by two of the present authors. The eastern side of the fault has been uplifted so that the $S{\check{o}}changri$ formation of the $Okch{\check{o}}n$ system cropped out in the zone of the Great Limestone series. All the previous workers thought that the $S{\check{o}}changri$ formation rests on the Great Limestone series, but the present study found an overthrust having a strike of $N8^{\circ}E$ and dip of $30^{\circ}NW$ between them, and the $S{\check{o}}changri$ formation has thrusted over the Great Limestone series at the central part of the study area. In the southern and northern parts of this uplifted $S{\check{o}}changri$ formation, the Great Limestone series rests unconformably on it. In the eastern part of the study area where the Mt. Dangdu is located and the previous workers thought that the $S{\check{o}}changri$ formation rests on the Great Limestone series, Precambrian basement rock whose age is older than 1720+50 m.y. crops out in the northern part of the east-west trending high angle fault, and the Great Limestone series rests unconformably on the basement.

• Journal of KSNVE
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• v.4 no.2
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• pp.221-230
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• 1994

This paper deals with the dynamic stability and the nonlinear behavior of a check valve system. The nonlinear equations of motion of fluid-valve interation model are derived, which are composed of the unsteady Bernoulli's equation included the jet flow mechanism and equation of motion of a check valve formulated by one degree of freedom. Also, the derived equations of motion are nondimensionalized. According to the change of the nondimensional parameters, the stabilities of the system are analyzed, and the nonlinear interaction responses of the check valve and the passing flow rate are obtained. As the results, the stability charts are constructed for the variation of nondimensional parameters. It is shown that self-excited vibrations exist in a check valve system. And also the Hopf bifurcation and the periodic doubling are found. The presented theoretical model of a check valve system can be utilized to the design and operation of a piping system with the check valve.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.6
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• pp.487-493
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• 2004

In this Paper, we propose a lighting system for the stable detection of check defects of the CRT panel through the analysis of the lighting interaction between the lighting unit and the CRT panel. The check defect is very difficult to detect reliably because of its high sensitivity according to the direction of incident light. At first, we model the physical shape of check defects using SEM image. And then we apply physics based illumination model to investigate the optical characteristics of the check defect. Finally, we propose a lighting system for the stable detection of check defect. Experimental results show the feasibility of the proposed lighting system for check inspection.

• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.355-370
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• 2003

In offline check systems, a client does not have to pay the exact amount. Instead, a client refunds the difference between the check value and the paid amount. In most offline systems, clients can not spend the remainder. But if the refund can be made spendable, it would provide a more convenient payment method. In this paper, we present a new offline system, which allows refunds to be reused as payments. In our system, the shop issues a new check using its private key for the difference. This new check, called the refund check, can be spent in the same way as checks issued by the bank. If the refund check is deposited to, or refunded at the bank, the bank charges the issuer of the check for the amount. The form of a check in this system is much simpler than previous check systems. It also uses a more flexible and efficient denomination method. The refund check is unlinkable to the check used in the payment where the refund check was issued. This system provides coin and owner tracing mechanisms to reinforce controls on illegal use of anonymous checks and was designed with consideration to the atomicity of transactions.

• Journal of Information Technology Services
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• v.11 no.2
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• pp.197-211
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• 2012

This paper describes how to derive audit criterion, audit domain, detail technology, and functional check items which are core of hospital information system, consisting of OCS, EMR, and PACS. Using the check items listed above, we investigated the objective validity for the construction audit of hospital information system. As a result, the derived audit criterion, audit domain, detail technology, and functional check items were verified as check items for audit. Since using the current audit check items of public area is insufficient to construct efficient, reliable, and stable hospital information system, we suggest adopting the hospital information system audit area, audit check items, and process that are presented in this paper.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.4
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• pp.501-508
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• 2019

In this paper, a study on a wireless check-up method of test equipment for captive flight test(CFT) was conducted. For CFT, test equipment is mounted on a POD, and check-up is carried on the test equipment's. For check-up the POD wirelessly, battery, power distribution unit, wireless communication devices were designed within the POD, and a check-up device is designed outside of the POD. Once the external check-up device sends a 'start signal' to the POD, it performs the overall check-up procedures and transmits the 'end signal' to the external check-up device. Detailed check-up results are stored in an internal storage device, and are possible to read from external check-up device if necessary, thereby improving the reliability of the wireless check-up. By implementing and applying these wireless check-up system, the reliability of the check-up was enhanced by dynamical and movable check-up, and safety is guaranteed as the check-up was carried without access to the aircraft.

• Convergence Security Journal
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• v.20 no.2
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• pp.145-153
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• 2020

The aviation safety policy master plan is promoting the development of aviation safety management technology applying the 4th industrial revolution technology with the goal of establishing a flawless aviation safety management system and establishing a future aviation safety infrastructure. The master plan includes the establishment of various aviation safety management systems such as aircraft fault management using AI & Big data and flight training system using VR/AR. Currently, the Air Force is promoting a flight safety management system using new technology under the goal of building smart air force. Therefore, this study intends to apply the 4th Industrial Revolution technology to the aircraft condition check system that finally checks the safety of the aircraft before flight. The Air Force conducts airframe flaw checks and pre-flight aircraft check. In this study, we architect the airframe flaw check system using AI and drones, and the pre-flight aircraft condition check system using the IoT and big data for more precise and detailed check of aircraft condition and flawlessness check.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.1
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• pp.32-43
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• 2014

Worldwide, air transport demand of this century is expanding rapidly, and each countries' demand is also increasing. Thus a number of low-cost carriers emerged in existing air transportation business sector and airman qualification check work regarding aviation safety management is increasing too. As the remedy for the result of aviation safety audit by ICAO and FAA in 2001 that governmental activity for aviation safety had been performed by a small number of aviation safety inspectors, airman qualification inspection system implemented by airlines was improved and the government has established the system that authorized airman qualification inspectors check airmen qualification with airlines according to the international trend. This study suggests the need of improvement of airman qualification inspection system that existing inspection system as the means of safety management can be transferred to Operations Safety Inspection(OSI) activity which is compliant with international standards.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.6
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• pp.803-812
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• 1998

In this study, testing equipment with which several kinds of valves can be tested was composed. Two kinds of tilting check valves and a swing check valve were tested to analyze their dynamic characteristics. The results of the experiment showed that the tilting check valves protected the pump but that the swing check valve could not protect the pump when the reverse flow rate was high. Also the dynamic equation of the tilting check valve was formulated and simulated using system characteristic constant t$_{c}$ and one method of predicting t$_{c}$ by comparing the results of the simulation with the results of the experiment was proposed.sed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.1
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• pp.73-85
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• 2001

Electronic check schemes are more efficient than electronic coin scheme with respect to computational costs and the amount of information exchanged. In spite of these, difficulties in making a refund reusable and in representing the face value of a check have discouraged its development. In this paper, a new online electronic check system is presented, which solves the above problems. This system uses the partially blind signature to provide user anonymity and to represent the face value of a check. The partially blind signature enables us to make the format of refunds and initially withdrawn checks identical. Thus, it allows refunds to be reused to buy goods without any limitatiosn. Both initially withdrawn checks and refunds in our system guarantee untraceability as well as unlinkability. We also use a one-time secret key as the serial number of a check to increase the efficiency of payments. The presented check system also provides multiple offline shopping sessions to minimize the number of online messages handled by a bank. During the multiple offline shopping session, we use a one-way accumulator to provide non-repudiation service. We also analyze our new systems our new system\`s security, efficiency, and atomicity.