• Journal of KIISE:Databases
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• 제31권1호
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• pp.30-38
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• 2004

In many scientific and commercial applications such as Earth Observation System (EOSDIS) and mobile Phone services tracking a large number of clients, it is a daunting task to archive and index ever increasing volume of complex data that are continuously added to databases. To efficiently manage multidimensional data in scientific and data warehousing environments, R-tree based index structures have been widely used. In this paper, we propose a scalable technique called seeded clustering that allows us to maintain R-tree indexes by bulk insertion while keeping pace with high data arrival rates. Our approach uses a seed tree, which is copied from the top k levels of a target R-tree, to classify input data objects into clusters. We then build an R-tree for each of the clusters and insert the input R-trees into the target R-tree in bulk one at a time. We present detailed algorithms for the seeded clustering and bulk insertion as well as the results from our extensive experimental study. The experimental results show that the bulk insertion by seeded clustering outperforms the previously known methods in terms of insertion cost and the quality of target R-trees measured by their query performance.

• Journal of KIISE:Computing Practices and Letters
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• 제15권5호
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• pp.322-330
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• 2009

In order to utilize NAND flash memory as storage media which does not allow update-in-place and limits the number of block erase count, various garbage collection policies supporting wear-leveling have been investigated. Conventional garbage collection policies require cleaning-index calculation for the entire blocks to choose a block to be garbage-collected to support wear-leveling whenever a garbage collection is required, which results in performance degradation of system. This paper proposes a garbage collection policy which supports wear-leveling using a threshold value, which is in fact a variance of erase counts and by the maximum erase count of all blocks, without calculating the cleaning-index. During garbage collection, the erase cost is minimized by using the Greedy Policy if the variance is less than the threshold value. It achieves wear-leveling by excluding the block with the largest erase count from erase target blocks if the variance is larger than threshold value. The proposed scheme shows that a standard deviation approaches to zero as the erase count of blocks approaches to its upper limit and the measured speed of garbage collection is two times faster than the conventional schemes.

• Journal of the Korean housing association
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• 제23권5호
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• pp.31-39
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• 2012

This study has analyzed the effect of the housing affordability improvement of the residents in the metropolitan areas, applying Transit Supportive Home Loan (TSHL) which extends the loan amount according to the transportation cost saving based on Location Efficiency Mortgage (LEM) System in the USA. The previous studies focused on introducing LEM system to Korea, whereas this study has analyzed TSHL effect for the first time, taking into account the situation in Korea. For analysis, The Transportation Savings (TS) is calculated and Housing Affordability Index (HAI) is drawn by applying increased TS and DTI (Debt to Income), so the improvements of housing purchasing ability is examined by HAI's improvement. As a result, transit commute 1 (having own car) and transit commute 2 (without having own cars) respectively produce the TS of monthly average 36 thousand won and 110 thousand won in comparison with car using commute. Each additional loan (TSHL) amounts to 16.57 million won and 54.07 million won. As the distance is farther and the house price cheaper, the improvement of HAI is more outstanding. City hall area showed the highest improvements of HAI by 9.3% (transit commute 1) and 21.9% (transit commute 2) increase, in comparison with car using commute.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.142-145
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• 2004

In this work, we have investigated the application of rapid thermal processing (RTP) and plasma enhanced chemical vapour deposition (PECVD) for surface passivation. Rapid thermal oxidation (RTO) has sufficiently low surface recombination velocities (SRV) $S_{eff}$ in spite of a thin oxides and short process time. The effective lifetime is increasing with an increase of the oxide thickness. In the same oxide thickness, The effective lifetime is independent on the process temperature and time. $S_{eff,max}$ is exponentially decreased with increasing oxide thickness. $S_{eff,max}$ can be reduced to 200 cm/s with only 10 nm oxide thickness. On the other hand, three different types of SiN are reviewed. SiN1 layer has a thickness of about 72 nm and a refractive index of 2.8. Also, The SiN1 has a high passivation quality. The effective lifetime and SRV of 1 $\Omega$ cm Float zone (FZ) silicon deposited with SiN1 is about 800 s and under 10 cm/s, respectively. The SiN2 is optimized for the use as an antireflection layer since a refractive index of 2.3. The SiN3 is almost amorphous silicon caused by less contents of N2 from total process. The effective lifetime on the FZ 1 ${\Omega}cm$ is over 1000 ${\mu}s$.

• Korean Journal of Clinical Pharmacy
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• 제22권4호
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• pp.291-303
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• 2012

As respiratory tract infections (RTI) account for about 60% of all antibiotic prescriptions in outpatient care setting, there are significant concerns about emerging resistance that are largely due to the excessive or inappropriate use of antibacterial agents for viral respiratory infections. This study was aimed to develop retrospective drug utilization review (DUR) program of antibiotics for RTIs using Delphi methods. Retrospective DUR criteria of antibiotics for RTIs were identified based on clinical practice guidelines and opinion of experts. Expert panel members were clinical doctors and pharmacists and Delphi method was applied by survey on 16 members of panels. The claim data from Korean Health Insurance Review & Assessment (HIRA) were used to examine trends in outpatient antibiotic prescription between Janunary to December of 2008. As results, Quality index for RTI was assessed for the claim type, antibiotics use of quantity, duration, number and cost. Antibiotic prescription rate for RTIs, Defined Daily Dose (DDD), and duration of antibiotics use were more recognized as significant quality index by experts' opinion. Use of first line agents suggested by guidelines was low and duration of antibiotics use was shorter compared to the recommendations. Antibiotics were over prescribed for RITs. However, dose and duration of antibiotics were under-used.

• The Journal of the Korea institute of electronic communication sciences
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• 제12권1호
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• pp.139-146
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• 2017

The interest about Artificial Intelligence through the AlphaGo Match in Korea has been increasing rapidly. So far, very little has been done in Artificial Intelligence. The aim of this paper is to reveal technology convergence and to assess the country profile in the field of artificial intelligence(AI). Technology convergence map was created after extracting USPTO patent grants and Web of Science data and generating matrics in the field of AI. Several Indicators were obtained by extracting and calculating SCOPUS Data that KISTI has. According to USPTO patent grants, it shows that AI technology has a strong relationship with several sectors such as cost/price determination, image analysis, and surgery, etc. Also, AI has a active convergence with some fields of Electrical and Electronic Engineering, BioTechnologies, and Medicine etc. According to country profile analysis, Korea reaches a global average growth index. However, in terms of specialization index (SI) and average of relative citations (ARC), there is a large gap between Korea and research leading countries.

• Korean Journal of Environment and Ecology
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• 제28권2호
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• pp.171-181
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• 2014

This study was performed to prevent deforestation and forest degradation and vitalize REDD+ program through suitable site analysis at the 16 districts of South Korea. For this, we worked out profit potential, opportunity cost, carbon credits through making it use of conception of the Forest Carbon Index. As a results, Gyeonggi-do, Incheon Metropolitan City, Seoul Metropolitan Government, Daegu Metropolitan City, Gwangwon-do included in the top 5 among the 16 districts of South Korea. In case of Gyeonggi-do as best suitable site, reduction of carbon emission was best high due to reduction area of deforestation. And profit potential was also high in accordance with practice of REDD+ program. Furthermore, we proposed four plans to activate REDD+ program in South Korea on the basis of the results.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제48권2호
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• pp.73-80
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• 2003

An experiment was carried out at the Field Laboratory of the Department of Crop Botany, Bangladesh Agricultural University, Mymensingh from March to July, 2001 to investigate the effect of biofertilizers on morpho-physiological characters of okra. The experiment was laid out in a randomized complete block design with four replications. There were nine treatments such as $\textrm{T}_0$ (control), $\textrm{T}_1$ (Azotobacter biofertilizer), $\textrm{T}_2$ (Azospirillum biofertilizer), $\textrm{T}_3$ (Azotobacter+Azospirillum biofertilizers), $\textrm{T}_4$ (Azotobacter+Cowdung 5 ton $\textrm{ha}^{-1}$), $\textrm{T}_5$ (Azospirillum+Cowdung 5 ton $\textrm{ha}^{-1}$), $\textrm{T}_6$(Azotobacter+Azospirillum+Cowdung 5 ton $\textrm{ha}^{-1}$), $\textrm{T}_7$ (Cowdung 5 ton $\textrm{ha}^{-1}$) and $\textrm{T}_8$ (60% Nitrogen). The experimental results revealed that significant variations exist among the treatments regarding morphological characters e.g. plant height, number of leaves/plant, stem base diameter, tap root length, and physiological characters like, root dry weight, leaf area index and crop growth rate. Number of leaves/plant, stem base diameter, root length, root dry weight, leaf area index and crop growth rate were found higher in $\textrm{T}_4$, $\textrm{T}_5$, $\textrm{T}_6$ and $\textrm{T}_8$ than the others. In all the parameters, $\textrm{T}_8$ gave the similar result with biofertilizers in combination with cowdung treatments and $\textrm{T}_7$ showed identical with $\textrm{T}_0$ (control). Biofertilizer treatments had insignificant effect on 1000-seed weight(g). Experimental results mentioned above revealed that morpho-physioligical characters of okra could be modified by the application of biofertilizer+cowdung. However, biofertilizers+Cowdung treatments were comparable to $\textrm{T}_8$(60% Nitrogen) in this study. This suggests that $\textrm{T}_4$ or $\textrm{T}_6$ or $\textrm{T}_5$ were more benificial in environmentally friendly okra cultivation and may be used as an alternative of inorganic nitrogen by saving cost of production and sustaining productivity.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제14권1호
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• pp.85-91
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• 2014

This paper relates with the VSDA (Variable stepsize Square contour Decision directed Algorithm) adaptive equalization algorithm that is used for the minimization of the intersymbol interference due to the distortion which occurs in the time dispersive channel for the transmission of 16-QAM signal.. In the conventional SCA, it is possible to compensates the amplitude and phase in the received signal that are mixed with the intersymbol interference by the constellatin dependent constant by using the 2nd order statistics of the transmitted signal. But in the VSDA, it is possible to the increasing the equalization performance by adding the concept of distance adjusted approach for constellation matching and the cost function of decision directed. We compare the performance of VSDA and SCA algorithm by the computer simulation. For this, the equalizer output signal constellation, residual isi, maximum distortion and MSE were used in the performace index. As a result of computer simulation, the VSDA algorithm has better than the SCA in convergence speed, but it gives nearly same equalization performance in other index.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• 제22권3_1spc호
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• pp.518-524
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• 2013

Recently, probabilistic assessments of nuclear power plant components have generated interest in the nuclear industries, either for the efficient inspection and maintenance of older nuclear plants or for improving the safety and cost-effective design of newly constructed nuclear plants. In the present paper, the partial safety factor (PSF) of wall-thinned nuclear piping is evaluated based on a reliability index method, from which the effect of each statistical variable (assessment parameter) on a certain target probability is evaluated. In order to calculate the PSF of a wall-thinned pipe, a limit state function based on the load and resistance factor design (LRFD) concept is first constructed. As for the reliability assessment method, both the advanced first-order second moment (AFOSM) method and second-order reliability method (SORM) are employed to determine the PSF of each probabilistic variable. The present results can be used for developing maintenance strategies considering the priorities of input variables for structural integrity assessments of wall-thinned piping, and this PSF concept can also be applied to the optimal design of the components of newly constructed plants considering the target reliability levels.