• Title/Summary/Keyword: 흐름량

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The Effect of Additives on the Properties of Zn Electrode in Zn/AgO Secondary Battery (Zn/AgO Secondary Battery용 아연 양극의 성능에 미치는 첨가제의 영향)

  • Park, Kyung-Wha;Kim, Chang-Hwan;Moon, Kyung-Man
    • Journal of the Korean Electrochemical Society
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    • v.6 no.3
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    • pp.196-202
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    • 2003
  • We investigated the effect of both 4 types additives and $0.5wt\%\;Pb_3O_4$ which have been reported to show an improvement on the performance of Zinc anode. And Experimental methods such as corrosion potential measurement, potentiodynamic polorization test and charging-discharging cycle life test were carried out in $40 wt\%$ KOH with $Pb_3O_4(0.5, \;10\;&\;2.0wt\%)$ and 4 types additives $(0.4wt\%\;of\;Ca(OH)_2$, 0.025M of Citrate, Tartrate and Gluconate). Corrosion potential was shifted to high direction and also changed to high and low direction repeatedly with increasing of $Pb_3O_4$ quantity. However by adding $0.5wt\%\;Pb_3O_4$, corrosion potential shifted to low direction and showed stable condition. Furthermore it was well known that corrosion resistance was predominantly increased compared to no addition and improved charging-discharging property with adding additives. By SEM analysis, it was concluded that the morphology of surface in case of only $0.5wt\%\;Pb_3O_4$ addition was nearly the same as that of Tartrate additive and in the other additives such as $Ca(OH)_2$, Citrate, Tartrate and Gluconate, their morphologies showed dendrite growth. Eventually it was thought that the additive of Tartrate indicated comparatively good corrosion resistance effect as well as charging-discharging property improvement among those four types additives.

A Study on the Systematic Integration of WASP5 Water Quality Model with a GIS (GIS와 WASP5 수질모델의 유기적 통합에 관한 연구)

  • 최성규;김계현
    • Spatial Information Research
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    • v.9 no.2
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    • pp.291-307
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    • 2001
  • In today's environmental engineering practice, many technologies such as GIS have been adopted to analyze chemical and biological process in water bodies and pollutants movements on the land surface. However, the linkage between spatially represented land surface pollutants and the in-stream processes has been relatively weak. This lack of continuity needs to develop a method in order to link the spatially-based pollutant source characterization with the water quality modeling. The objective of this thesis was to develop a two-way(forward and backward) link between ArcView GIS software and the USEPA water quality model, WASP5. This thesis includes a literature review, the determination of the point source and non-point source loadings from WASP5 modeling, and the linkage of a GIS with WASP5 model. The GIS and model linkage includes pre-processing of the input data within a GIS to provide necessary information for running a model in the forms of external input files. The model results has been post-processed and stored in the GIS database to be reviewed in a user defined form such as a chart, or a table. The interface developed from this study would provide efficient environment to support the easier decision making form water quality management.

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Behavior and pillar stability of enlarged existing parallel tunnels (기존 병설터널의 확폭에 따른 터널 거동 및 필라 안정성 분석)

  • Lee, Myeong-Han;Kim, Bumjoo;Jang, Yeon-Soo;Yun, Ji-Nam;Park, Hyun-Gon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.15 no.5
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    • pp.537-546
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    • 2013
  • Traffic congestion in existing tunnels has increased due to increased traffic volume and enlarged vehicles. Enlarging existing tunnels has advantages over constructing new tunnels by reducing land purchasing costs as well as minimizing natural environment destruction. In fact, many overseas projects for enlarging existing tunnels have been reported. Thus, it appears that the demand on enlarging existing tunnels continues to rise in Korea in near future. Nonetheless, the studies related to the enlarged tunnels have been relatively rare since there have been few tunnel enlargement projects in Korea. In the present study, the tunnel behavior and the stability of rock pillar when enlarging existing parallel tunnels were investigated by performing FE analysis and using existing theory and empirical relationships. Four different enlarging cases, depending on the enlargement types and directions, were examined in the study. According to the results, for the tunnels with the same pillar width after enlarged, the uni-laterally enlarged tunnel indicated 5 to 20% higher crown settlement compared to the bi-laterally enlarged tunnel, and for the tunnel with the narrowest pillar, the highest shotcrete stress was observed. Also, the strength/stress ratio for rock pillar was more than 1.0 for all four enlargement cases, and the Matsuda's method was found to give higher strength/stress ratio by about 50% compared to the Peck's method.

Comparison of Sampling Techniques for Passive Internet Measurement: An Inspection using An Empirical Study (수동적 인터넷 측정을 위한 샘플링 기법 비교: 사례 연구를 통한 검증)

  • Kim, Jung-Hyun;Won, You-Jip;Ahn, Soo-Han
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.6
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    • pp.34-51
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    • 2008
  • Today, the Internet is a part of our life. For that reason, we regard revealing characteristics of Internet traffic as an important research theme. However, Internet traffic cannot be easily manipulated because it usually occupy huge capacity. This problem is a serious obstacle to analyze Internet traffic. Many researchers use various sampling techniques to reduce capacity of Internet traffic. In this paper, we compare several famous sampling techniques, and propose efficient sampling scheme. We chose some sampling techniques such as Systematic Sampling, Simple Random Sampling and Stratified Sampling with some sampling intensities such as 1/10, 1/100 and 1/1000. Our observation focused on Traffic Volume, Entropy Analysis and Packet Size Analysis. Both the simple random sampling and the count-based systematic sampling is proper to general case. On the other hand, time-based systematic sampling exhibits relatively bad results. The stratified sampling on Transport Layer Protocols, e.g.. TCP, UDP and so on, shows superior results. Our analysis results suggest that efficient sampling techniques satisfactorily maintain variation of traffic stream according to time change. The entropy analysis endures various sampling techniques well and fits detecting anomalous traffic. We found that a traffic volume diminishment caused by bottleneck could induce wrong results on the entropy analysis. We discovered that Packet Size Distribution perfectly tolerate any packet sampling techniques and intensities.

Development of the video-based smart utterance deep analyser (SUDA) application (동영상 기반 자동 발화 심층 분석(SUDA) 어플리케이션 개발)

  • Lee, Soo-Bok;Kwak, Hyo-Jung;Yun, Jae-Min;Shin, Dong-Chun;Sim, Hyun-Sub
    • Phonetics and Speech Sciences
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    • v.12 no.2
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    • pp.63-72
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    • 2020
  • This study aims to develop a video-based smart utterance deep analyser (SUDA) application that analyzes semiautomatically the utterances that child and mother produce during interactions over time. SUDA runs on the platform of Android, iPhones, and tablet PCs, and allows video recording and uploading to server. In this device, user modes are divided into three modes: expert mode, general mode and manager mode. In the expert mode which is useful for speech and language evaluation, the subject's utterances are analyzed semi-automatically by measuring speech and language factors such as disfluency, morpheme, syllable, word, articulation rate and response time, etc. In the general mode, the outcome of utterance analysis is provided in a graph form, and the manger mode is accessed only to the administrator controlling the entire system, such as utterance analysis and video deletion. SUDA helps to reduce clinicians' and researchers' work burden by saving time for utterance analysis. It also helps parents to receive detailed information about speech and language development of their child easily. Further, this device will contribute to building a big longitudinal data enough to explore predictors of stuttering recovery and persistence.

Comparative Analysis of Export Behaviors of Pyeongtaek-Dangjin Port and Daesan Port (평택.당진항과 대산항의 수출행태의 비교분석)

  • Mo, Soowon
    • Journal of Korea Port Economic Association
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    • v.29 no.3
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    • pp.25-37
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    • 2013
  • This study investigates the export behavior of port of Pyeongtaek-Dangjin and Daesan. The monthly data cover the period from January 2002 to December 2012. This paper tests whether the exchange rate and the industrial production are stationary or not, rejecting the null hypothesis of a unit root in each of the level variables and of a unit root for the residuals from the cointegration at the 5 percent significance level. The error-correction model is estimated to find that Daesan port is faster than Pyeongtaek-Dangjin in adjusting the short-run disequilibrium. This paper finds that the exchange rate coefficient of Daesan port is higher than that of Pyeongtaek-Dangjin port, while the industrial production coefficient of the former is much smaller than that of the latter. The industrial production coefficient is, however, much higher than the exchange rate coefficient in both ports. The rolling regression shows that the influence of exchange rate and industrial production tends to increase in Pyeongtaek-Dangjin port but tends to decrease in Daesan. The impulse response functions indicate that export volumes respond much greater to the positive shocks in industrial production than in exchange rate, and the exchange rate shock decays very fast, while the industrial production shock lasts very long.

Preparation and Characterization of Grafted Maleic Anhydride onto Polypropylene by Reactive Extrusion (반응 압출을 통한 PP-g-MA 제조 및 특성평가)

  • Kang, Dong-Jin;Lee, Sung-Hyo;Pal, Kaushik;Park, Chan-Young;Zhang, Zhen Xiu;Bang, Dae-Suk;Kim, Jin-Kuk
    • Polymer(Korea)
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    • v.33 no.4
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    • pp.358-363
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    • 2009
  • Maleic anhydride-grafted polypropylene has been widely used to improve the interfacial interaction between the components in PP/polar polymer blends and PP/filler composites and to maximize the physical properties and thermal properties. In this paper. the maleic anhydride (MAH)-grafted polypropylene (co-PP) was fabricated through reactive extrusion process with di-cumyl peroxide (DCP) as an initiator. The grafting degree of MAH depending on the contents of DCP and MAH was investigated by FT-IR spectra and chemical titration. The grafting degree increased with increasing MAH concentration and also showed maximum value at 0.06 wt% of DCP concentration. Melt flow index (MFI) of the grafted copolymer was increased with increasing the contents of MAH. The DSC and TGA analysis data indicate the melting temperature and thermal degradation of PP depending on the grafting degree of MAH.

Analysis of debris flow simulation parameters with entrainment effect: a case study in the Mt. Umyeon (연행작용을 고려한 우면산 토석류 모의 매개변수 특성분석)

  • Lee, Seungjun;An, Hyunuk;Kim, Minseok;Lim, Hyuntaek
    • Journal of Korea Water Resources Association
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    • v.53 no.9
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    • pp.637-646
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    • 2020
  • The shallow landslide-trigerred debris flow in hillslope catchments is the primary geological phenomenon that drives landscape changes and therefore imposes risks as a natural hazard. In particular, debris flows occurring in urban areas can result to substantial damages to properties and human injuries during the flow and sediment transport process. To alleviate the damages as a result of these debris flow, analytical models for flow and damage prediction are of significant importance. However, the analysis of debris flow model parameters is not yet sufficient, and the analysis of the entrainment, which has a significant influence on the flow process and the damage extent, is still incomplete. In this study, the effects of erosion and erosion process on the flow and the impact area due to the change in the soil parameters are analyzed using Deb2D model, a flow analysis model of debris developed in Korea. The research is conducted for the case of the Mt. Umyeon landslide in 2011. The resulting impacted area, total debris-flow volume, maximum velocity and inundated depth from the Erosion model are compared to the field survey data. Also, the effect of the entrainment changing parameters is analyzed through the erosion shape and depth. The debris flow simulation for the Raemian and Shindong apartment catchment with the consideration of entrainment effect and erosion has been successful. Each parameter sensitivity could be analyzed through sensitivity analysis for the two basins based on the change in parameters, which indicates the necessity of parameter estimation.

Numerical experiments for the changes of currents by reclamation of land in Kwangyang Bay (매립으로 인한 광양만의 유동변화 수치실험)

  • 추효상
    • Journal of Environmental Science International
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    • v.11 no.7
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    • pp.637-650
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    • 2002
  • This study presents an investigation of the changes of the currents in Kwangyang Bay due to the construction of harbor, reclamation and coastal developments. Currents were simulated by the numerical experiments with a diagnostic multi-level model and using the seasonal oceanographic data of temperature, salinity and ocean current. The values of kinetic and potential energies for the currents were calculated in cases of three topographical changes; before coastal developments, the existing state and after completion of the development project in Kwangyang Bay. The changes of currents due to the coastal developments are as follow; Kinetic energies of tide induced residual currents and wind driven currents decreased by 35~40 percent and 5 percent respectively, however those of density currents increased by 10 percent since the decrease of the coastal areas. Kinetic energy of residual currents including tide induced residual currents, density currents and wind driven currents reduced by 10 percent compared with before the coastal developments. Decrease of current velocity was greatest in summer. Therefore, in summer it was assumed that the Kwangyang Bay is more easily polluted by stratification and decrease of residual current than before the coastal developments carried out.

Stock Prediction Model based on Bidirectional LSTM Recurrent Neural Network (양방향 LSTM 순환신경망 기반 주가예측모델)

  • Joo, Il-Taeck;Choi, Seung-Ho
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.11 no.2
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    • pp.204-208
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    • 2018
  • In this paper, we proposed and evaluated the time series deep learning prediction model for learning fluctuation pattern of stock price. Recurrent neural networks, which can store previous information in the hidden layer, are suitable for the stock price prediction model, which is time series data. In order to maintain the long - term dependency by solving the gradient vanish problem in the recurrent neural network, we use LSTM with small memory inside the recurrent neural network. Furthermore, we proposed the stock price prediction model using bidirectional LSTM recurrent neural network in which the hidden layer is added in the reverse direction of the data flow for solving the limitation of the tendency of learning only based on the immediately preceding pattern of the recurrent neural network. In this experiment, we used the Tensorflow to learn the proposed stock price prediction model with stock price and trading volume input. In order to evaluate the performance of the stock price prediction, the mean square root error between the real stock price and the predicted stock price was obtained. As a result, the stock price prediction model using bidirectional LSTM recurrent neural network has improved prediction accuracy compared with unidirectional LSTM recurrent neural network.