• Journal of Information Management
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• v.24 no.2
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• pp.36-53
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• 1993

Nowadays we usually act based on information in order to act effectively, we should enlarge our access to information of course, we have several methods to choose from, but commercial databases are the most advantageous. One reason is that everyone has equal access to commercial databases. As a result, people or companies who use commercial database information skillfully have a distince advantage over those who don't commercial database services in japan have been changing rapidly since their birth more than twenty years ago. For example, the distribution mode of databases is changing : from the original batch(off line) to on-line and most recently to the coexistence of batch and on line with the advent of CD-ROM. It is important for us to keep up with the new trends in databases, and to utilize them effectively as a tool in the information age.

• The KIPS Transactions:PartC
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• v.18C no.3
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• pp.151-156
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• 2011

Google Android, which is one of the popular smart phone platforms, employs a security model based on application permissions. This model intends to reduce security threats by protecting inappropriate accesses to system resources from applications, but this model has a few problems. First, permission requested by an application cannot be granted selectively. Second, once the permission has been granted it is maintained until the application is uninstalled. Third, applications may acquire powerful permissions through user ID sharing without any notice to users. In order to overcome these limitations, we designed and implemented a flexible application permission management scheme. The goal of our scheme is to enhance security and user convenience while keeping compatibility to original platform. We also verified the operation of our scheme with real applications on Android emulator.

• The KIPS Transactions:PartC
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• v.15C no.4
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• pp.253-262
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• 2008

Providing Quality-of-Service (QoS) guarantee requires the reservation of resource needed to accommodate the traffic flow of service for which resource reservation protocol (RSVP) was introduced. However, if any RSVP-capable router on the path fails to accommodate the traffic flow due to lack of resource, the flow is not allowed no matter how much surplus resources other routers on the path have. In order to solve this problem, this paper proposes a resource reservation method with available resource migration between RSVP-capable routers in which the routers use the recently developed latency optimized fair queuing scheduler. The results of the simulation applying the proposed method to an evaluation network show that it may yield the gain of up to 165% compared to that in the original one in terms of the number of admitted flows.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.7
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• pp.522-527
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• 2013

In this paper, We studied the change of surface and variation of elements on both electrodes of hydrogen generator of alkaline electrolysis in use of FE-SEM and SIMS. We used the stainless steel 316(600 ${\mu}m$) as electrode in condition of 25%KOH, $60^{\circ}C$ Temperature. The results show that the intensity of elements (C, Si, P, S, Ti, Cr, Mn, Fe, Ni, Mo) of Positive Electrode are decreased as much as about $10^1{\sim}10^3 $than the original electrode. Thickness of Positive Electrode is decreased about 40 ${\mu}m$ after chemical reaction. The negative electrode, however, shows a slight variation in the intensity of elements (C, Si, P, Fe, Ni, Mn, Mo) but Change of thickness and surface' shape of electrode show nothing after chemical reaction. The change in thickness and variation of Stainless Steel 316 cause the lifetime of electrode to be shorted. We also observed hydrogen, oxygen, potassium in both electrodes. Especially, The potassium is increased in proportional with depth of positive electrode. this means the concentration of alkali solutions is changed. and so we have to supply alkaline solution to generator in order to produce same quantity of hydrogen gas continuously. we hope that this study gives a foundation to develop the electrode for hydrogen generator of alkaline electrolysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.379-385
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• 2015

This paper proposes the hardware architecture of high performance ALF(Adaptive Loop Filter) for efficient filter coefficient estimation. In order to make the original image which has high resolution and high quality into highly compressed image effectively and also, subjective image quality into improved image, the ALF technique of HEVC performs a filtering by estimating filter coefficients using statistical characteristics of image. The proposed ALF hardware architecture is designed with a 2-step pipelined architecture for a reduction in performance cycle by analysing an operation relationship of Cholesky decomposition for the filter coefficient estimation. Also, in the operation process of the Cholesky decomposition, a square root operation is designed to reduce logic area, computation time and computation complexity by using the multiplexer, subtracter and comparator. The proposed hardware architecture is designed using Xilinx ISE 14.3 Vertex-7 XC7VCX485T FPGA device and can support 4K UHD@40fps in real time at a maximum operation frequency of 186MHz.

• Informatization Policy
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• v.24 no.3
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• pp.42-66
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• 2017

This study investigated the ecological change of public software industry, comparing the pre and post structure of industry network based on the application of the regulation restricting large company participation in public software market. For this purpose, we used big data of the software market from Korea Public Procurement Service and used the SNA(Social Network Analysis) methodology which is being actively used in the area of social science recently. Finally, we highlighted the contribution of open public data. By analyzing order and contract data of the public software industry for 3 years - from 2013 to 2015 - we found out two main things. First, we observed that Power Law distribution had been going on in the public software industry, regardless of the external impact of regulation. Second, despite the existence of such Power Law distribution, we also observed the ecological change of industry structure from year to year. We presented the implication of such findings and discussed the advantage of open public data as the original motivator of this study.

• Tunnel and Underground Space
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• v.17 no.2 s.67
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• pp.119-127
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• 2007

Based on the critical plane approach, a methodology far predicting the anisotropic strength ot transversely isotropic rock is Proposed. It is assumed that the rock failure is governed by Hoek-Brown failure criterion. In order to establish an anisotropic failure function, Mohr envelope equivalent to the original Hoek-Brown criterion is used and the strength parameters m, s are expressed as scalar functions of orientation. The conjugate gradient method, which is one of the robust optimization techniques, is applied to the failure function for searching the orientation giving the maximum value of the anisotropic function. While most of the existing anisotropic strength models can be applied only when the stress condition is the same as that of conventional triaxial compression test, the proposed model can be applied to the general 3-dimensional stress conditions. Through the simulation of triaxial compression tests for transversely isotropic rock sample, the validity of the proposed method is investigated by comparing the predicted triaxial strengths and inclinations of failure plane.

• Korean Journal of Hydrosciences
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• v.7
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• pp.37-49
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• 1996

This study aims at suggesting an alternative to improve flood controling capacity according to the cument design criteria for the existing Soyanggang Multi-purpose Dam which was constructed 20 years ago as the largest dam in Korea. The peak inflow of the adopted probable maximum flood (PMF) at the time of construction was 13,500 $m^3$/s. However, the newly estimated peak inflow of the PMF is 18,000 $m^3$/s which is 1.34 times bigger than the original one. This is considered to be due to the accumulation of the reliable flood and storm event records after construction, and due to the increasing tendency of the local flood peaks according to the influence of world-wide weather change. The new estimation of the probable maximum precipitation (PMP) was based on the hydro-meteorological method suggested by the guideline of the World Meteorological Organization (WMO). The unit hydrograph which was applied for the estimation of PMF was derived through linear programming algorithm by minimizing the sum of absolute deviations of the calculated and recorded flood hydrographs. In order to adopt the newly estimated PMF as a design flood, following four alternatives were compared : (1) allocation of more flood control space by lowering the normal high water level, (2) construction of a new spillway in addition to the existing spillway, (3) construction of a new dam which has relevant flood control storage at the upstream of the Soyanggang dam, (4) raising the existing dam crest. The preliminary evaluation of these alternatives resulted in that the second alternative is most economic and feasible. So as to stably cope with the newly estimated PMF by meeting all the current functions of the multipurpose dam, a detailed study of an additional spillway tunnel has to be followed.

• Conservation Science in Museum
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• v.18
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• pp.51-64
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• 2017

The Bracket clock in the collection of the Korean Christian Museum at Soongsil University underwent conservation treatment for a special exhibition. The compositional analysis showed that the body was made of brass plated with gold by fire-gilding(gold amalgam process), while the dial was identified as pure copper coated with enamel. The hands were made of steel. Remnants of adhesive tape on the dial were cleaned, followed by the addition of a protective coating. In order to restore it to a condition as similar to its original form as possible, replacements for missing parts were newly constructed out of brass and were connected to the hands and the dial. The dial was then fixed to the body using an acrylic support. The compositional analysis and conservation treatment have left the clock in stable condition and readily available for exhibitions and future studies.

• Conservation Science in Museum
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• v.11
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• pp.1-8
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• 2010

Conservation re-treatment of dagger and scabbard in Gyeongju National Museum, which were excavated from Gyerim-ro Tomb No. 14 (Treasure No. 635) was carried out after a wide-scale dissembling in order for publishing a report and holding a special exhibition. The interior shape of the iron dagger which was disclosed by ornament plates was confirmed by X-ray investigation. The results of XRF analysis which was used to analyse compositions of the golden ornament plates reveal that having more than 3% of copper distinguishes it from other Silla gold artifacts. The conservation treatment progressed in a way that surface contaminants were removed and insecure areas were consolidated. The original shape of the iron dagger and scabbard was found after adhering and restoration. With the ornament plates staying on the iron dagger, a stand in acrylic for display and storage was made, which is able to place the dagger and scabbard in the safest way.