• KIPS Transactions on Computer and Communication Systems
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• v.4 no.2
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• pp.47-56
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• 2015

In an energy saving server cluster environment, the power modes of servers are controlled according to load situation, that is, by making ON only minimum number of servers needed to handle current load while making the other servers OFF. This algorithm works well under normal circumstances, but does not guarantee QoS under abnormal circumstances such as sharply rising or falling loads. This is because the number of ON servers cannot be increased immediately due to the time delay for servers to turn ON from OFF. In this paper, we propose a new prediction algorithm of the power consumption for improving QoS under not only normal but also abnormal circumstances. The proposed prediction algorithm consists of two parts: prediction based on the conventional time series analysis and prediction adjustment based on trend analysis. We performed experiments using 15 PCs and compared performance for 4 types of conventional time series based prediction methods and their modified methods with our prediction algorithm. Experimental results show that Exponential Smoothing with Trend Adjusted (ESTA) and its modified ESTA (MESTA) proposed in this paper are outperforming among 4 types of prediction methods in terms of normalized QoS and number of good reponses per power consumed, and QoS of MESTA proposed in this paper is 7.5% and 3.3% better than that of conventional ESTA for artificial load pattern and real load pattern, respectively.

• Journal of the Korea Society of Computer and Information
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• v.18 no.11
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• pp.77-86
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• 2013

In this paper, we propose a fast video retargeting method which preserves the contents of a video and converts the image size. Since the conventional Seam Carving which is the well-known content-aware image retargeting technique uses the dynamic programming method, the repetitive update procedure of the accumulation energy is absolutely needed to obtain seam. The energy update procedure cannot avoid the processing time delay because of many operations by the image full-searching. By applying the proposed method, frames which have similar features in video are classified into a scene, and the first frame of a scene is resized by the modified Seam Carving where multiple seams are extracted from candidate seams to reduce the repetitive update procedure. After resizing the first frame of a scene, all continuous frames of the same scene are resized with reference to the seam information stored in the previous frame without the calculation of the accumulation energy. Therefore, although the fast processing is possible with reducing complexity and without analyzing all frames of scene, the quality of an image can be analogously maintained with an existing method. The experimental results show that the proposed method can preserve the contents of an image and can be practically applied to retarget the image on real time.

• Journal of the Korea Society of Computer and Information
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• v.25 no.4
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• pp.165-172
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• 2020

In this paper we propose an uses on-device-based edge computing technology and big data analysis methods through the use of on-device-based edge computing technology and analysis of big data, which are distributed computing paradigms that introduce computations and storage devices where necessary to solve problems such as transmission delays that occur when data is transmitted to central centers and processed in current general smart factories. However, even if edge computing-based technology is applied in practice, the increase in devices on the network edge will result in large amounts of data being transferred to the data center, resulting in the network band reaching its limits, which, despite the improvement of network technology, does not guarantee acceptable transfer speeds and response times, which are critical requirements for many applications. It provides the basis for developing into an AI-based facility prediction conservation analysis tool that can apply deep learning suitable for big data in the future by supporting intelligent facility management that can support productivity growth through research that can be applied to the field of facility preservation and smart factory industry with integrated hardware technology that can accommodate these requirements and factory management and control technology.

• Journal of the Korea Convergence Society
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• v.12 no.12
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• pp.93-106
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• 2021

Blenderbot 2.0 is a dialogue model representing open domain chatbots by reflecting real-time information and remembering user information for a long time through an internet search module and multi-session. Nevertheless, the model still has many improvements. Therefore, this paper analyzes the limitations and errors of BlenderBot 2.0 from three perspectives: model, data, and dialogue. From the data point of view, we point out errors that the guidelines provided to workers during the crowdsourcing process were not clear, and the process of refining hate speech in the collected data and verifying the accuracy of internet-based information was lacking. Finally, from the viewpoint of dialogue, nine types of problems found during conversation and their causes are thoroughly analyzed. Furthermore, practical improvement methods are proposed for each point of view, and we discuss several potential future research directions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.3
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• pp.229-235
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• 2021

Globally, due to climate change and urbanization, problems with water cycle destruction in urban areas frequently occur. In order to solve this problem, LID technique is being actively conducted the application in urban and research. In this study, some areas of the new city located in Busan was constructed using a widely used SWMM model to verify the effectiveness of the LID technique. This is to present a plan to maximize the efficiency of urban water cycle of the stormwater management target figure and the LID scale calculation method. In addition, the efficiency of runoff reduction using stormwater storage basin was analyzed in urban development projects. By calculating the scale of customized LID for each sub basin, the amount of runoff and peak runoff after LID application was reduced by 86.8 % and 69.5 %, respectively. Depending on the application of the stormwater storage basin, the reduction effect of peak runoff from 0.5 m³/s to 4.9 m³/s and delay effect of 8 minutes to 10 minutes was shown.

• Journal of the Korean earth science society
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• v.42 no.1
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• pp.76-87
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• 2021

In this study, temporal trend of researches in earthquake with groundwater level, water quality, radon, remote sensing, electrical resistivity, gravity, and geomagnetism was searched from 2001 to 2020, using the journals indexed in Web of Science, and the number of articles published in international journals was counted in relation to the occurrences of earthquakes (≥Mw 5.0, ≥Mw 6.0, ≥Mw 7.0, ≥Mw 8.0, and ≥Mw 9.0). The number of articles shows an increasing trend over the studied period. This is explained by that studies on earthquake precursor and seismic monitoring becomes active in various fields with integrated data analysis through the development of remote sensing technology, progress of measurement equipment, and big data. According to Mann-Kendall and Sen's tests, gravity-related articles exhibit an increasing trend of 1.30 articles/yr, radon-related articles (0.60 articles/yr), groundwater-related articles (0.70 articles/yr), electrical resistivity-related articles (0.25 articles/yr), and remote-sensing-related articles (0.67 articles/yr). By cross-correlation analysis of the number of articles in each field with removing trend effect and the number of earthquakes of ≥Mw 5.0, ≥Mw 6.0, ≥Mw 7.0, ≥Mw 8.0, and ≥Mw 9.0, radon and remote sensing fields exhibit a high cross-correlation with a delay time of one year. In addition, large-scale earthquakes such as the 2004 and 2005 Sumatra earthquake, the 2008 Sichuan earthquake, the 2010 Haiti earthquake, and the 2010 Chile earthquake are estimated to be related with the increase in the number of articles in the corresponding periods.

• Journal of the Korea Society for Simulation
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• v.18 no.4
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• pp.39-47
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• 2009

Recently, the threat of DDoS attacks is increasing and many companies are planned to deploy the DDoS defense solutions in their networks. The DDoS attack usually transmits heavy traffic data to networks or servers and they cannot handle the normal service requests because of running out of resources. Since it is very hard to prevent the DDoS attack beforehand, the strategic plan is very important. In this work, we have conducted modeling and simulation of the DDoS attack by changing the number of servers and estimated the duration that services are available. In this work, the modeling and simulation is conducted using OPNET Modeler. The simulation result can be used as a parameter of trade-off analysis of DDoS defense cost and the service's value. In addition, we have presented a way of estimating the cost effectiveness in deployment of the DDoS defense system.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.2
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• pp.285-290
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• 2023

Compressors are widely used in high-speed electronic systems and are used to reduce the number of operands in multiplier. The proposed compressor is constructed based on the m-GDI(: modified gate diffusion input) to reduce the propagation delay time. This paper is compared the performance of compressors by applying 4-2, 5-2 and 6-2 m-GDI compressors to the multiplier, respectively. As a simulation results, compared to the 8-bit Dadda multiplier using the 4-2 and 6-2 compressor, the multiplier using the 5-2 compressor is reduced propagation delay time 13.99% and 16.26%, respectively. Also, the multiplier using the 5-2 compressor is reduced PDP(: Power Delay Product) 4.99%, 28.95% compared to 4-2 and 6-2 compressor, respectively. However, the multiplier using the 5-2 compression circuit is increased power consumption by 10.46% compared to the multiplier using the 4-2 compression circuit. In conclusion, the 8-bit Dadda multiplier using the 5-2 compressor is superior to the multipliers using the 4-2 and 6-2 compressors. The proposed circuit is implemented using TSMC 65nm CMOS process and its feasibility is verified through SPECTRE simulation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.22-29
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• 2023

In the evaluation of seismic performance for structural materials and components, the loading rate and axial force can have a significant impact. Due to time-delay effects between input and output displacements, It is difficult to apply high-rate displacement in cyclic tests and hybrid simulations. Additionally, the difficulty of maintaining a consistent vertical load in the presence of lateral displacement has limited fast and real-time tests performed while maintaining a constant vertical load. In this study, slow, fast cyclic tests and real-time hybrid simulations were conducted to investigate the rate dependency and the influence of vertical loads of Isolation Bearing. In the experiment, the FLB System including an Adaptive Time Series (ATS) compensation and a state estimator was constructed for real-time control of displacement and vertical load. It was found that the vertical load from the superstructure and loading rate can have a significant impact on the strength of the seismic isolation bearing and its behavior during an earthquake. When conducting experiments for seismic performance evaluation, they must be implemented to be similar to reality. This study demonstrates the excellent performance of the system built and used for seismic performance evaluation and enables accurate and efficient seismic performance evaluation.

• Clinical and Experimental Reproductive Medicine
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• v.28 no.2
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• pp.95-103
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• 2001

연구목적: 본 연구는 생쥐 preantral follicles의 체외 배양 조건을 확립하고 이를 기초로 높은 체외 발달률 그리고 산자 생산률을 얻고자 하였다. 연구재료 및 방법 : Preantral follicles의 oocyte-granulosa cell complexes (OGCs)는 생후 12일된 FI ($C57BL{\times}CBA$)으로부터 난소를 적출하여 효소를 이용한 방법을 통해 획득하였다. 회수된 complexes는 10일 또는 12일 동안 체외 성장을 위해 Transwell-COL membrane insert로 옮겨졌고 5% FBS, 100 mIU/ml FSH, 100 mIU/ml hMC가 첨가된 ${\alpha}MEM$에서 배양되었다. 체외 성숙을 위해 1.5 IU/ml hCG가 첨가된 ${\alpha}MEM$에서 18 hrs 배양을 실시하였다. 그 후 M16에서 수정능력이 획득된 정자와 수정을 하여 4 hrs, 7 hts, 9 hrs 후에 10% FBS가 첨가된 modified M16 배양액에서 4일간 배양하거나 또는 bovine cumulus cell과 co-culture를 실시하였다. 그리고 형태적으로 정상적인 22개의 상실배와 포배를 2마리의 위임신 대리모 (ICR)의 자궁에 이식하여 산자 생산을 유도하였다. 결과: 1) OGCs 크기가 mouse preantral follicles의 핵 및 세포질 성숙에 미치는 영향을 조사하였을 때 $120{\sim}150{\mu}m$의 preantral follicles (MII: 33.0%, 난할률: 36.7%, 상실배 이상; 20.9%)은 핵 및 세포질 성숙에 있어서 $70{\sim}110{\mu}m$ (MII: 12.2%, 난할률: 10.2%, 상실배 이상: 4.8%)보다 더 높았다(p<0.001). 2)체외 성장기간의 연장이 mouse preantral follicles의 핵 및 세포질 성숙에 미치는 영향을 조사하였을 때 10일 (난할률: 38.2%)은 12일 (난할률: 20.0%)보다 난할률에서만 더 높았다 (p<0.01). 3) 체외 수정 시간의 연장이 mouse preantral follicle의 세포질 성숙에 미치는 영향을 조사하였을 때 9 hrs (난할룰 31.5%, 상실배 이상: 14.3%)은 4 hrs (난할률: 17.5%, 상실배 이상: 4.8%), 7 hrs (난할률: 20.4%, 상실배 이상: 6.1%) 보다 세포질성숙에 있어서 유의하게 높은 발달률을 나타냈다 (p<0.01). 4) 공배양이 mouse preantral follicle의 세포질성숙에 미치는 영향을 조사하였을 때 공배양 (상실배 이상: 17.4%)을 실시했을 때와 M16 (상실배 이상17.4%)에서 배양되었을 때는 차이가 없었다. 5)preantral follicle의 크기 ($120{\sim}150{\mu}m$), 체외 성장기간 (10일), 체외 수정 기간 (9시간), 배양 환경 (단지 medium만 존재)의 적절한 결과들을 종합하여 수행하였을 때 MII 성숙률, 난할률, 상실배 이상의 발달률은 30.2%, 39.3%, 22.5%이었고 총 22개의 상실배 및 포배를 2마리의 대리모에 이식했을 때 1마리가 임신했고 1마리의 산자를 생산했다. 결론: 따라서, 본 실험은 preantral follicle을 이용한 체외 배양 시스템이 생쥐 oocyte를 공급하는 또 다른 방법으로 효과적으로 이용될 수 있다는 것을 시사한다.