• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2806-2811
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• 2013

New technologies such as multi-antenna and small cell were proposed as key technology for the next generation mobile system to cope with the explosively increasing mobile data traffic. In particular, heterogeneous mobile communication network which can improve spatial reuse factor by exploiting macro and small cells simultaneously is attracting attention. However, the heterogeneous network has a problem that the utilization of small cells becomes low because the transmit power of macro base stations is much higher than that of small base stations and then the probability that mobile stations are attached to the macro base stations becomes high. This problem is dominant in uplink. The concept of cell range expansion bias to mitigate the problem was proposed by 3GPP and the corresponding standardization is in progress. In this paper, we analyze the downlink performance of the heterogeneous mobile communication network based on a system level simulator with the cell range expansion bias in terms of average cell spectral efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.3
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• pp.527-533
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• 2018

Recently, the device-to-device (D2D) communication has been conceived as the key technology for the next-generation mobile communication systems. The neighbor discovery in which the nearby users are found, is essential for the proper operation of the D2D communication. In this paper, we propose new neighbor discovery scheme based on deep learning technology which has gained a lot of attention recently. In the proposed scheme, the neighboring users can be found using the uplink pilot transmission of users only, unlike conventional neighbor discovery schemes in which direct pilot communication among users is required, such that the signaling overhead can be greatly reduced in our proposed scheme. Moreover, the neighbors with different proximity can also be classified accordingly which enables more accurate neighbor discovery compared to the conventional schemes. The performance of our proposed scheme is verified through the tensorflow-based computer simulations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3518-3524
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• 2015

Spatial and time variation of the precipitation in Korea is high, therefore, more than 2/3 of the annual precipitation is concentrated during the rainy season. Climate change also causes the intensive rainfall in the area of dense population, thus the occurrence frequency of the heavy flood in the impervious area has been increased. Therefore, the structural food mitigation measures such as the construction of the higher design frequency stormwater pipes, pumping stations, and/or detention ponds. The flood bypass tunnel or retention storage is also one of the efficient structures to mitigate flood damage in the urban area. However, the economic feasibility has been controversial because the flood bypass tunnel might be used once or twice a year. To solve the problem, the multi-functional tunnel for the urban traffic and flooding bypass has been considered. In this study, the design criteria of the road and water tunnel has been analysed and the composite design criteria is proposed for the multi-functional tunnel which is expected to be constructed.

• Journal of KIISE:Information Networking
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• v.30 no.4
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• pp.461-473
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• 2003

Multimedia applications are much more sensitive to QoS(Quality of Service) than text based ones due to their data continuity. In order to provide a fast moving MH(Mobil Host) using multimedia application with a consistent QoS,an efficient call admission mechanism is in need. This paper proposes the 2SCA(2-Step Call Admission) scheme based on cal admission scheme using pripority to guarantee the consistent QoS for mobile multimedia applications. A calls of MH are classified new calls, hand-off calls, and QoS upgrading calls. The 2SCA is composed of the basic call admission and advanced call admission; the former determines the call admission based on bandwidth available in each cell and the latter determines the call admission by applying DTT(Delay Tolerance Time), PQeueu(Priority Queue), and UpQueue(Upgrade Queue) algorithm according to the type of each call blocked at the basic call admission stage. In order to evaluate the performance of our mechanism, we measure the metrics such as the dropping probability of new calls, dropping probability of hand-off calls, and bandwidth utilization. The result shows that the performance of our mechanism is superior to that of existing mechanisms such as CSP(Complete Sharing Policy), GCP(Guard Channel Policy) and AGCP(Adaptive Guard Channel Policy).

• Journal of KIISE:Databases
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• v.31 no.6
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• pp.684-698
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• 2004

The Hippocratic database model recently proposed by Agrawal et al. incorporates privacy protection capabilities into relational databases. Since the Hippocratic database is based on the relational database, it needs extensions to be adapted for XML databases. In this paper, we propose the Hippocratic XML database model, an extension of the Hippocratic database model for XML databases and present an efficient access control mechanism under this model. In contrast to relational data, XML data have tree-like hierarchies. Thus, in order to manage these hierarchies of XML data, we extend and formally define such concepts presented in the Hippocratic database model as privacy preferences, privacy policies, privacy authorizations, and usage purposes of data records. Next, we present a new mechanism, which we call the authorization index, that is used in the access control mechanism. This authorization index, which is Implemented using a multi-dimensional index, allows us to efficiently search authorizations implied by the authorization granted on the nearest ancestor using the nearest neighbor search technique. Using synthetic and real data, we have performed extensive experiments comparing query processing time with those of existing access control mechanisms. The results show that the proposed access control mechanism improves the wall clock time by up to 13.6 times over the top-down access control strategy and by up to 20.3 times over the bottom-up access control strategy The major contributions of our paper are 1) extending the Hippocratic database model into the Hippocratic XML database model and 2) proposing an efficient across control mechanism that uses the authorization index and nearest neighbor search technique under this model.

• Journal of Korean Society of Forest Science
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• v.101 no.1
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• pp.130-137
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• 2012

This study has conducted to develop new gabion wall systems with vegetation base materials for stream bank stability and rapid rehabilitation. Vegetation base materials are primarily compounded with fine soil, organic composts and peat moss as plant fibers, a water retainer and a soil improver. Normally gabion wall systems resist the lateral earth pressures or stream power by their own weight. Therefore, fill material must have suitable weight, compressive strength and durability to resist the loading, as well as the effects of water and weathering. In this project, 100 to 200-mm clean, hard stones are basically specified, and about 50-mm rubbles are also used. Test application of new gabion wall system carried out in the stream bank of a small stream in the Gwangreung experimental forest, belonging to Korea Forest Research Institute (KFRI) in December 16th, 2006. As a result of the analysis of hydraulic stability of new gabion wall system, gabion wall system has highest threshold shear stress when the gabion wall covered by vegetation. New gabion wall system is highly resistant to sliding and overturning because safety coefficients exceed 1.5. As a result of term of slope stability analysis of new gabion wall system by Bishop and Fellenius methods, stability of stream bank was highly increased after the construction of gabion wall. Therefore, new gabion wall system is effective to stabilize unstable stream bank.

• Korean Security Journal
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• no.61
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• pp.333-352
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• 2019

In January and August 2019, there were amendments to the Unfair Competition and Trade Secrets Protection Act (UCPA) and the Industrial Technology Protection Act(ITPA). These amendments will contribute to technology protection. But these amendments need to be supplemented further. In the area of civil remedies, despite the introduction of treble damages in the case of the UCPA and ITPA, the provisions related to the submission of supporting data have not been maintained. Therefore, it is necessary to recognize the claim of the other party as true if it is maintained at the level of the revised Patent Act and the scope of submission of supporting data. And the enforcement of the case of compulsory submission for the calculation of damages, and the order of filing documents are not followed. ITPA, on the other hand, has introduced the compensation for damages, but there is no provision for estimating the amount of damages. Therefore, it is necessary to estimate the amount of lost profits, profits, and royalties. In the area of criminal remedies, both the UCPA and ITPA have raised the penalty, but the sentencing regulations are not maintained. In addition, although the recent outflow of technology has expanded beyond organizational deviations to organizational outflows, amendments need to be made in relation to the serious consequence for the punishment of related juristic persons, such as companies involved in it. It should be noted that Japan and the United States have corporate regulations and regulations. In addition, in relation to the confiscation system, Act on Regulation and Punishment of criminal proceeds concealment require that domestic defenses be confiscated by defense industry technology, while trade secrets and industrial technologies are confiscated only by "foreign" outflows, and an amendment is necessary.

• Journal of Korean Society on Water Environment
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• v.18 no.2
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• pp.201-212
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• 2002

The objective of this study was to investigate the treatment efficiency, kinetics, and morphological characteristics of biofilm in upflow $Biobead^{(R)}$ process, a kind of biological aerated filter(BAF). The $Biobead^{(R)}$ system showed high removal rates of $COD_{Mn}$(76~83%), $BOD_5$(67~88%) and SS(71~91%) for food wastewater with high salt concentration ($>4,000mg/{\ell}$) under short reaction times(2~3hrs). Even at aerobic condition, the system had high treatment efficiency for both T-N (51~63%) and T-P(62~81%). The removal kinetics of $COD_{Mn}$, $BOD_5$, T-N, T-P, and $Cl^-$ in the $Biobead^{(R)}$ system showed a plug-flow pattern with reaction rate constants($hr^{-1}$) of 0.58, 0.63, 0,30, 0.48, and 0.38 respectively. A backwashing process to remove excess biomass and filtered solids was needed at least once during 22-hour operation at $0.5kg\;BOD\;m^{-3}{\cdot}d^{-1}$ loading. At the higher loading($1.0kg\;BOD\;m^{-3}{\cdot}d^{-1}$) the backwashing interval was shorten by 8 hours. The COD, BOD, T-N, and T-P were removed from 43 to 66% only by aerobic biodegradation. The SS was removed over 70% by the filtering of $Biobead^{(R)}$ media in the treatment system. The first one of three serial Biobead reactors showed the highest removal values for $COD_{\alpha}$(52.3%), $COD_{Mn}$(38.8%), BOD(62.5%), and T-N(40.0%). The SS and T-P had the highest removal values(47.5% and 29.2%) at the second one of the serial reactors. The biofilm had non-homogeneous spatial distribution and the colonies were embedded in the sunk area of the Biobead. The thickness of the biofilm was very thin ($5.0{\sim}29.4{\mu}m$) compared to the biofilm thickness($200{\sim}300{\mu}m$) used in other BAF systems.

• Childhood Kidney Diseases
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• v.9 no.1
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• pp.76-82
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• 2005

Purpose : Regional anticoagulation with trisodium citrate for continuous renal replacement therapy(CRRT) is an effective and safe method, with lower bleeding risk. However it is not widely used because of complex current protocols used to prevent anticipated metabolic derangements. We evaluated simplified regional anticoagulation protocols with ACD-A(R) solution and commercially available calcium-containing dialysis solution. Methods : The medical records of twenty-eight patients who underwent CRRT were reviewed. Hemofilter life span according to the anticoagulation method used was compared, and laboratory findings at Pre- and 48 hours post-CRRT initiation were compared in the citrate-based CRRT group. Results : Of the twenty-eight Patients, five patients underwent citrate-based CRRT Hemofilter life span was 1.60 $\pm$ 0.72 days, showing no significant differences with the hemofilter life span in the heparin based and LMWH based CRRT group. No patients experienced hemorrhagic complications. PT, aPTT, sodium, t$CO_{2}$, iCa levels showed no difference in pre- and post-CRRT. Total calcium levels were increased. At the recommended postfilter iCa level, j.e., 0.25-0.39 mmol/L, all five patients needed increased amount of citrate infusion, and Ca infusion requirement was decreased. Conclusion : Simplified regional citrate anticoagulation with calcium-containing dialysate is an effective and safe method, and is not associated with increased hemofilter clotting. However, increased postfilter iCa level is recommended.

• Journal of Life Science
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• v.21 no.2
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• pp.194-201
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• 2011

Caudal-related homeodomain proteins play critical roles in intestine development and maintenance from Drosophila to humans. The loss or reduction of CDX1 and CDX2 are known to be associated with colon cancers. It has been well known that colorectal carcinogenesis is associated with serious oxidative stress and that catalase is decreased in colon carcinomas. However, the underlying molecular mechanisms remain elusive. Here, we report that Caudal-related homeodomain proteins positively regulate catalase expression in both Drosophila and humans. We found that Drosophila caudal heterozygotes have a decreased catalase expression and increased ROS generation in the hindgut, and that the overexpression of Caudal increases catalase promoter activity and catalase mRNA levels. We also found that CDX1 and CDX2 up-regulate catalase promoter activity and protein levels in HCT116 cells - human colorectal carcinoma cell lines. The level of catalase protein in several colorectal carcinoma cell lines was associated with CDX1 expression. These results suggest that CDX1 and CDX2 may be involved in intestinal homeostasis and tumorigenesis via regulation of catalase expression.