• Title/Summary/Keyword: spatial and temporal patterns

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A Study on Flow Characteristics of Lid-Driven Square Cavity (정방형 벨트구동 캐비티의 흐름특성에 관한 연구)

  • 김진구;조대환;김춘식;이영호
    • Journal of Advanced Marine Engineering and Technology
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    • v.21 no.4
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    • pp.430-436
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    • 1997
  • Time-dependent Flow characteristics of a two-dimensional lid-driven square cavity flow of six high Reynolds numbers, $10^4 2{\times}lO^4., 3{\times}l0^4, 5{\times}lO^4, 7.5{\times}lO^4$ and $10^5$ were investigated. A convection conservative difference scheme based upon SOLA to maintain the nearly 2nd-order spatial accuracy was adopted on irregular grid formation. Irregular grid number is $80{\times}80$ and its minimum size is about 1/400 of the cavity height(H) and its maximum is about 1/53 H. The result shows that at Re= $10^4$, periodic migration of small eddies appearing in corner separation region and its temporal sinusoidal fluctuation are represented. And another critical Reynolds number which shows the commencement of flow randomness emerging from the periodic fluctuation is assumed to be around Re= $1.5{\times}10$. At five higher Reynolds numbers ($2{\times}lO^4., 3{\times}l0^4, 5{\times}lO^4, 7.5{\times}lO^4$ and $10^5$), an organizing structure of four consecutive vortices similar to a Moffat vortex at two lower corners is revealed from time-mean flow patterns.

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Isolation of Genes Specifically Expressed in Different Developmental Stages of Pleurotus ostreatus Using Macroarray Analysis

  • Lee, Seung-Ho;Joh, Joong-Ho;Lee, Jin-Sung;Lim, Jong-Hyun;Kim, Kyung-Yun;Yoo, Young-Bok;Lee, Chang-Soo;Kim, Beom-Gi
    • Mycobiology
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    • v.37 no.3
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    • pp.230-237
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    • 2009
  • The oyster mushroom (Pleurotus ostreatus) is one of the most important edible mushrooms worldwide. The mechanism of P. ostreatus fruiting body development has been of interest both for the basic understanding of the phenotypic change of the mycelium-fruiting body and to improve breeding of the mushrooms. Based on our previous publication of P. ostreatus expressed sequence tag database, 1,528 unigene clones were used in macroarray analysis of mycelium, fruiting body and basidiospore developmental stages of P. ostreatus. Gene expression profile databases generated by evaluating expression levels showed that 33, 10, and 94 genes were abundantly expressed in mycelium, fruiting body and basidiospore developmental stages, respectively. Among them, the genes specifically expressed in the fruiting body stage were further analyzed by reverse transcription-polymerase chain reaction and Northern blot to investigate temporal and spatial expression patterns. These results provide useful information for future studies of edible mushroom development.

Missing Pattern of the Tidal Elevation Data in Korean Coasts (한반도 연안 조위자료의 결측 양상)

  • Cho, Hong-Yeon;Ko, Dong-Hui;Jeong, Shin-Taek
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.23 no.6
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    • pp.496-501
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    • 2011
  • The missing data patterns of tidal elevation data in Korean coasts are analysed and provided. The missing interval of the data is displayed for all stations using the missing data indicator matrix in order to identify the overall missing pattern. The spatial and temporal missing rates are also estimated. The total missing rate of tidal elevation data is low. However, most of the missing is mainly derived from just 1 or 2 specific stations. The autocorrelation function of the consecutive missing interval data also shows that the missing interval occurs randomly.

Walkability on Ramps by Gait Analysis (보행자세해석에 의한 경사로의 보행성)

  • 유남형
    • Journal of the Korean Institute of Landscape Architecture
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    • v.23 no.2
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    • pp.157-166
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    • 1995
  • To investigate walkability of ramps, walking patterns of 18 healthy adults,12 aged 20 to 26 and 6 aged 68 to 76,were studied at free,rhythm constrained walking up or down ramp using goniometer and footswitch Ramp inclinations were set 4,8,12,16,20 degrees. The results were as follows. 1)The step length of subjects were decreased significantly in12$^{\circ}C$′or 16′free downramp walking. With regard to step length, some subject groups walked abnormally in 16" or 20" ramp walking 2) The step width of subjects were increased significantly in 12" or 16" ramp walking. 3) The cadence duration of some subject groups were increased in 12" upramp walking. 4) The double stance duration and double stance ratio of some subject groups were increased significantly in 8",12", or 16"upramp walking. 5) The maximum knee flexion angle of stance phase were increased in 12" ramp walking. 6)Most temporal parameters and spatial parameters of gait were increased or decreassd greatly between 4" ramp and 8" ramp or between 8′ramp and 12′ramp. But statistics significancy were not recognized 7) The results suggest that ramp inclination less than 8′(14%) -12′(21%) is desirable for the normal gait the ramp inclination must not exceed 16" -20" in unavoidable circumstances.

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Gated Recurrent Unit based Prefetching for Graph Processing (그래프 프로세싱을 위한 GRU 기반 프리페칭)

  • Shivani Jadhav;Farman Ullah;Jeong Eun Nah;Su-Kyung Yoon
    • Journal of the Semiconductor & Display Technology
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    • v.22 no.2
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    • pp.6-10
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    • 2023
  • High-potential data can be predicted and stored in the cache to prevent cache misses, thus reducing the processor's request and wait times. As a result, the processor can work non-stop, hiding memory latency. By utilizing the temporal/spatial locality of memory access, the prefetcher introduced to improve the performance of these computers predicts the following memory address will be accessed. We propose a prefetcher that applies the GRU model, which is advantageous for handling time series data. Display the currently accessed address in binary and use it as training data to train the Gated Recurrent Unit model based on the difference (delta) between consecutive memory accesses. Finally, using a GRU model with learned memory access patterns, the proposed data prefetcher predicts the memory address to be accessed next. We have compared the model with the multi-layer perceptron, but our prefetcher showed better results than the Multi-Layer Perceptron.

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Optimization of Memristor Devices for Reservoir Computing (축적 컴퓨팅을 위한 멤리스터 소자의 최적화)

  • Kyeongwoo Park;HyeonJin Sim;HoBin Oh;Jonghwan Lee
    • Journal of the Semiconductor & Display Technology
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    • v.23 no.1
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    • pp.1-6
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    • 2024
  • Recently, artificial neural networks have been playing a crucial role and advancing across various fields. Artificial neural networks are typically categorized into feedforward neural networks and recurrent neural networks. However, feedforward neural networks are primarily used for processing static spatial patterns such as image recognition and object detection. They are not suitable for handling temporal signals. Recurrent neural networks, on the other hand, face the challenges of complex training procedures and requiring significant computational power. In this paper, we propose memristors suitable for an advanced form of recurrent neural networks called reservoir computing systems, utilizing a mask processor. Using the characteristic equations of Ti/TiOx/TaOy/Pt, Pt/TiOx/Pt, and Ag/ZnO-NW/Pt memristors, we generated current-voltage curves to verify their memristive behavior through the confirmation of hysteresis. Subsequently, we trained and inferred reservoir computing systems using these memristors with the NIST TI-46 database. Among these systems, the accuracy of the reservoir computing system based on Ti/TiOx/TaOy/Pt memristors reached 99%, confirming the Ti/TiOx/TaOy/Pt memristor structure's suitability for inferring speech recognition tasks.

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Analysis of C. elegans VIG-1 Expression

  • Shin, Kyoung-Hwa;Choi, Boram;Park, Yang-Seo;Cho, Nam Jeong
    • Molecules and Cells
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    • v.26 no.6
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    • pp.554-557
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    • 2008
  • Double-stranded RNA (dsRNA) induces gene silencing in a sequence-specific manner by a process known as RNA interference (RNAi). The RNA-induced silencing complex (RISC) is a multi-subunit ribonucleoprotein complex that plays a key role in RNAi. VIG (Vasa intronic gene) has been identified as a component of Drosophila RISC; however, the role VIG plays in regulating RNAi is poorly understood. Here, we examined the spatial and temporal expression patterns of VIG-1, the C. elegans ortholog of Drosophila VIG, using a vig-1::gfp fusion construct. This construct contains the 908-bp region immediately upstream of vig-1 gene translation initiation site. Analysis by confocal microscopy demonstrated GFP-VIG-1 expression in a number of tissues including the pharynx, body wall muscle, hypodermis, intestine, reproductive system, and nervous system at the larval and adult stages. Furthermore, western blot analysis showed that VIG-1 is present in each developmental stage examined. To investigate regulatory sequences for vig-1 gene expression, we generated constructs containing deletions in the upstream region. It was determined that the GFP expression pattern of a deletion construct (${\Delta}-908$ to -597) was generally similar to that of the non-deletion construct. In contrast, removal of a larger segment (${\Delta}-908$ to -191) resulted in the loss of GFP expression in most cell types. Collectively, these results indicate that the 406-bp upstream region (-596 to -191) contains essential regulatory sequences required for VIG-1 expression.

Production of Homozygous Transgenic Mud Loach (Misgurnus mizolepis) II. pFV4CAT Transfer by Microinjection (외래 유전자가 이식된 동형접합성 미꾸라지 생산 II. pFV4CAT이 이식된 $F_0$ 생산)

  • 남윤권;김철근;김동수
    • Journal of Aquaculture
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    • v.10 no.1
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    • pp.33-37
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    • 1997
  • construct containing reporter gene(pFV4CAT) regulated by carp $\beta$-actin promoter was microinjected into the one-cell stage egg of mud loach (Misgurnus mizolepis), and was successfully expressed, possibly by the integration into the genome. Both mean hatching success and early survival of the microinjected groups were not significantly different with those of control groups (P>0.05). The incidence of transgene was ranged from 7 to 48% based on the PCR and/or Southern blot analyses with the DNA prepared from fin or blood tissue. The spatial and temporal patterns of expression of the pFV4CAT gene, measured by in situ immunohistochemical analysis peroxidase-conjugated anti-CAT antibody, were variable among the experimental individuals. These results suggest that carp $\beta$-actin promoter is effective to express other transgene in mud loach, such that this promoter can be useful in the generation of valuable transgenic mud loach.

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The Exceedance Patterns of O3 Air Quality Standards from 31 Monitoring Stations in Seoul (오존의 환경기준 초과양상에 대한 연구)

  • Kim, Min-Young;Choi, Ye-Jin;Kim, Ki-Hyun
    • Journal of the Korean earth science society
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    • v.23 no.8
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    • pp.683-696
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    • 2002
  • In this work. we investigated the ozone data sets that exceeded ambient air quality standards from 31 air quality monitoring stations dispersed across the Seoul metropolitan city during the period covering 1990 and 2000. To specifically describe spatial dependency of high level O$_3$ occurrence, we grouped our data into four different geographical ozone exceedance is much longer in SW than the other three sectors. When we compared the exceedance data in terms of occurrence frequency, the month of maximum frequency differed slightly among different sectors. Examination of long-term exceedance trend indicated that its frequency increased continuously from all sectors over the past years, although slightly opposite patterns existed in their absolute values. Most importantly, its peak occurrence frequency seemed to center in very recent years such as 1998 (NE sector) and 2000 (ail pattern sectors except NE). Consequently, we were able to describe the existence of certain patterns of ozone exceedance data sets in terms of both temporal and spatial scales.

A study on Spatiotemporal Variations of distribution characteristics in Artificial Rivers of the Brackish Water Zone (기수역 인공하천에서 시공간적 수질분포 특성 연구)

  • Kim, Yoon-Jeong;Choi, Ok Youn;Han, Ihn-Sup
    • Journal of Korean Society of Water Science and Technology
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    • v.26 no.6
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    • pp.89-97
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    • 2018
  • The purpose of this reaserch is to analyze the charateristics of water quality in space through the operation of ARA River in Artificial Rivers of the Brackish Water Zone. The spatial distribution measured water temperature and salt levels for the surface, middle and deep layers by dividing the four areas of Incheon, Sicheon, Gyeyang and Gimpo. Water temperature did not vary much by water depth and branch, and its purpose is to maintain stable water environment through correlation analysis and operation. To examine the temporal and spatial distribution patterns of the Arachon, we measured DO on the Incheon branch, Sicheon, Gyeyang and Gimpo branch twice a month, and on the surface, the temperature level, The water temperature did not vary much by depth and location, and the water temperature in January and March tended to rise from Incheon to Gimpo, with the average difference of 1.1 degrees during the same period. The salinity difference between Incheon and Gimpo sites was 3.3 psu deep and 5.4 psu deep. In particular, floodgates from July to September are found to be less than 10psu overall, which is considered to be a gas due to the effects of floods and the inflow of Gulpo Stream. D.O. is located in some areas due to summer rains. The hypoxic layer has been identified.Analysis of seasonal data shows that water temperature and DO are strongly correlated in autumn. It was found that the water temperature and salt levels in the fall showed a weak correlation.