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  • Title/Summary/Keyword: 구조계산

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Investigation of Gas Transport Properties of Polymeric Membranes having Different Chain Lengths Via Molecular Dynamics (MD) (분자동역학을 이용한 고분자 주쇄의 길이 변화에 따른 기체 투과 성능 연구)

  • Kang, Hoseong;Park, Chi Hoon
    • Membrane Journal
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    • v.28 no.1
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    • pp.67-74
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    • 2018
  • In the molecular dynamics study of polymeric membranes, it is very important to select the proper length of the polymer main chain because it requires a large number of constituent atoms and a long time to simulate the permeation behavior. In this study, we tried to investigate how the correlation between polymer main chain length and permeation behavior appears in actual molecular dynamics simulation results. Molecular dynamics were performed using the widely known commercial polymer Kapton(R) polyimide structure and the gas permeation behavior was simulated. The movement of the polymer main chain was not related to its length and the short main chain length did not act more actively. In addition, unlike the prediction that the end group of the polymer main chain is relatively easy to move, there are many cases where the atoms located at the middle of the polymer main chains have a higher movement than the atoms located at the end groups. Finally, permeabilities of the gas molecules was not affected by the length of the main chain and the end groups of the polymer, which indicates that the end effect should be carefully mentioned and followed by the verification process.

Zooplankton Community Structure and Copepod Production in the Seomjin River Estuary (섬진강 하구역의 동물플랑크톤 군집구조와 요각류 생산력 연구)

  • Youn, Seok-Hyun;Oh, Ghang-Sok;Chung, Mi-Hee
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.16 no.4
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    • pp.369-379
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    • 2010
  • Zooplankton community structure and copepod production in Seomjin River estuary were investigated at 10 stations along the salinity gradients from May 2009 to February 2010. Total zooplankton taxa were identified to be 31 in the study area and seasonal average abundance of zooplankton was 4,151ind.m3 during the study period. Zooplankton community was mainly composed of coastal species in dry season. However, brackish species dominated in upper or middle part of this estuary in flood season. This study showed that the growth rates of Acartia spp. and Paracalanus parvus s.l. measured from field experiments were regulated by the variations of Hater temperature and salinity; The annual copepod production estimated by dominant copepod species was 3.49gCm2yr1, and the relatively high production value could be explained by the high phytoplankton standing stocks and the mass occurrence of coastal and brackish species with relation to various salinity gradients in Seomjin River estuary.

Development of Structure Analysis Program for Jointed Concrete Pavement Applying Load Discretization Algorithm (하중변환 알고리듬을 적용한 줄눈 콘크리트 포장해석 프로그램 개발)

  • Yun, Tae-Young;Kim, Ji-Won;Cho, Yoon-Ho
    • International Journal of Highway Engineering
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    • v.5 no.4 s.18
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    • pp.1-11
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    • 2003
  • Recently, the new pavement design method considering Korean environment and the specification for improving performance of pavement are being developed in Korea. The Jointed Concrete Pavement Program Applying Load Discretization Algorithm (called HEART-JCP) is one of the results of Korea Pavement Research Project in Korea. HEART-JCP program is developed to analyze various loading condition using the load discretization algorithm without mesh refinement. In addition, it can be modified easily into multi-purpose concrete pavement nidyses program because of the modularized structure characteristic of HEART-JCP. The program consists of basic program part and load discretization part. In basic program part, the displacement and stress are computed in the concrete slab, sub-layer, and dowel bar, which are modeled with plate/shell element, spring element and beam element. In load discretization program part, load discretization algorithm that was used for the continuum solid element is modified to analyze the model with plate and shell element. The program can analyze the distributed load, concentrated load, thermal load and body load using load discretization algorithm. From the result of verification and sensitivity study, it was known that the loading position, the magnitude of load, and the thickness of slab were the major factors of concrete pavement behavior as expected. Since the result of the model developed is similar to the results of Westergaard solution and ILLISLAB, the program can be used to estimate the behavior of jointed concrete pavement reasonably.

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Design and Implementation of a 128-bit Block Cypher Algorithm SEED Using Low-Cost FPGA for Embedded Systems (내장형 시스템을 위한 128-비트 블록 암호화 알고리즘 SEED의 저비용 FPGA를 이용한 설계 및 구현)

  • Yi, Kang;Park, Ye-Chul
    • Journal of KIISE:Computer Systems and Theory
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    • v.31 no.7
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    • pp.402-413
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    • 2004
  • This paper presents an Implementation of Korean standard 128-bit block cipher SEED for the small (8 or 16-bits) embedded system using a low-cost FPGA(Field Programmable Gate Array) chip. Due to their limited computing and storage capacities most of the 8-bits/16-bits small embedded systems require a separate and dedicated cryptography processor for data encryption and decryption process which require relatively heavy computation job. So, in order to integrate the SEED with other logic circuit block in a single chip we need to invent a design which minimizes the area demand while maintaining the proper performance. But, the straight-forward mapping of the SEED specification into hardware design results in exceedingly large circuit area for a low-cost FPGA capacity. Therefore, in this paper we present a design which maximize the resource sharing and utilizing the modern FPGA features to reduce the area demand resulting in the successful implementation of the SEED plus interface logic with single low-cost FPGA. We achieved 66% area accupation by our SEED design for the XC2S100 (a Spartan-II series FPGA from Xilinx) and data throughput more than 66Mbps. This Performance is sufficient for the small scale embedded system while achieving tight area requirement.

Design and Implementation of Compact Ultra Wideband Patch Antenna Using L-Feed and Slot-Feed (L 급전 및 Slot 급전을 동시에 적용하는 광대역 소형 패치 안테나의 설계 및 구현)

  • Choi, Jong-In;Lee, Bomson
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.5
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    • pp.484-491
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    • 2013
  • In this paper, the method of designing a wideband antenna has been introduced through the design technique that simultaneously employs L- and slot-type feeds. Using the two kinds of feeds and additional fence structure, a compact wideband patch antenna has been realized. The size of the patch has been reduced by about 30 % based on the low frequency(824 MHz) and the full fractional bandwidth is wider than 100 %. The L-feed element is for the EM coupling feeding at the low frequency, while it functions as a feeding line for the power coupling through the slot at the high frequency. The proposed antenna has been designed not only for wideband operations but also for a proper array element with a reduced size. Thus, the foundation for developing the ultra wideband patch array antennas has been prepared. The fabricated antenna has been found to have good characteristics on V.S.W.R and the radiation patterns over the full bands. The experimental and computed results are shown to be in good agreement.

Conjugation of Landsat Data for Analysis of the Land Surface Properties in Capital Area (수도권 지표특성 분석을 위한 Landsat 자료의 활용)

  • Jee, Joon-Bum;Choi, Young-Jean
    • Journal of the Korean earth science society
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    • v.35 no.1
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    • pp.54-68
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    • 2014
  • In order to analyze the land surface properties in Seoul and its surrounding metropolitan area, several indices and land surface temperature were calculated by the Landsat satellites (e.g., Landsat 5, Landsat 7, and Landsat 8). The Landsat data came from only in the fall season with Landsat 5 on October 21, 1985, Landsat 7 on September 29, 2003, and Landsat 8 on September 16, 2013. The land surface properties used are the indices that represented Soil Adjusted Vegetation Index (SAVI), Modified Normalized Difference Wetness Index (MNDWI), Normalized Difference Wetness Index (NDWI), Tasseled cap Brightness, Tasseled cap Greenness, Tasseled cap Wetness Index, Normalized Difference Vegetation Index (NDVI) and Normalized Difference Built-up Index (NDBI) and the land surface temperature of the area in and around Seoul. Most indices distinguish very well between urban, rural, mountain, building, river and road. In particular, most of the urbanization is represented in the new city (e.g., Ilsan) around Seoul. According to NDVI, NDBI and land surface temperature, urban expansion is displayed in the surrounding area of Seoul. The land surface temperature and surface elevation have a strong relationship with the distribution and structure of the vegetation/built-up indices such as NDVI and NDBI. While the NDVI is positively correlated with the land surface temperature and is also negatively correlated with the surface elevation, the NDBI have just the opposite correlations, respectively. The NDVI and NDBI index is closely associated with the characteristics of the metropolitan area. Landsat 8 and Landsat 5 have very strong correlations (more than -0.6) but Landsat 7 has a weak one (lower than -0.5).

Characteristics of Precipitation over the East Coast of Korea Based on the Special Observation during the Winter Season of 2012 (2012년 특별관측 자료를 이용한 동해안 겨울철 강수 특성 분석)

  • Jung, Sueng-Pil;Lim, Yun-Kyu;Kim, Ki-Hoon;Han, Sang-Ok;Kwon, Tae-Yong
    • Journal of the Korean earth science society
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    • v.35 no.1
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    • pp.41-53
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    • 2014
  • The special observation using Radiosonde was performed to investigate precipitation events over the east coast of Korea during the winter season from 5 January to 29 February 2012. This analysis focused on the various indices to describe the characteristics of the atmospheric instability. Equivalent Potential Temperature (EPT) from surface (1000 hPa) to middle level (near 750 hPa) was increased when the precipitation occurred and these levels (1000~750 hPa) had moisture enough to cause the instability of atmosphere. The temporal evolution of Convective Available Potential Energy (CAPE) appeared to be enhanced when the precipitation fell. Similar behavior was also observed for the temporal evolution of Storm Relative Helicity (SRH), indicating that it had a higher value during the precipitation events. To understand a detailed structure of atmospheric condition for the formation of precipitation, the surface remote sensing data and Automatic Weather System (AWS) data were analyzed. We calculated the Total Precipitable Water FLUX (TPWFLUX) using TPW and wind vector. TPWFLUX and precipitation amount showed a statistically significant relationship in the north easterly winds. The result suggested that understanding of the dynamical processes such as wind direction be important to comprehend precipitation phenomenon in the east coast of Korea.

Field Case Study for the Productivity Analysis of B2 Reservoir, Donghae-1 Gas Field (동해-1 가스전 B2 저류층의 생산성 분석에 관한 Field Case Study)

  • Kwon Sun-Il;Ryou Sangsoo;Kwon Oukwang;Sung Wonmo
    • Journal of the Korean Institute of Gas
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    • v.5 no.1
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    • pp.60-72
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    • 2001
  • This paper presents the user-interactive productivity analysis model based on material balance as well as deliverability equations equipped with EOS model to perform a productivity analysis for Gorae V structure, Donghae-1 gas field. This model is designed to be able to analyse the productivity in the case of reservoir contacting with the aquifer. Also, in order to investigate the effect of condensation on productions, condensation phenomenon is considered as an apparent skin effect in the computation of bottomhole pressure from average reservoir pressure. By utilizing the developed model, we investigate the productivity analysis for B2 layer of Garae V structure with the various production cases in volumetric and non­volumetric reservoirs that contact with aquifer. From the results in the case of 5500 MMSCF/year of production and reservoir-aquifer contacting angle 270C with aquifer size of 10 times greater than reservoir, B2 layer could maintain peak production rate even after 8.5 years of production by considering the bottomhole pressure which is estimated above the operating pressure of 1298 psia. It is also found that condensate will be formed after 1100 days of production and existed throughout the reservoir at 1270 days. Note that the computed reservoir pressure of B2 layer is maintained sufficiently high enough for production due to the water influx into the reservoir, and skin effect caused by condensation is not significant.

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Research on Fault Tolerant Avionics Memory Design through Multi Level Cell Flash Memory Reliability Analysis (멀티 레벨 셀 플래시 메모리 신뢰성 분석을 통한 항공 전자장비용 내결함성 메모리 설계 연구)

  • Jeong, Sang-gyu;Jun, Byung-kyu;Kim, Young-mok;Chang, In-ki
    • Journal of Advanced Navigation Technology
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    • v.20 no.4
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    • pp.321-328
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    • 2016
  • Typical MLC NAND flash devices are considered less reliable than SLC NAND flash devices. Although raw bit error rate (RBER) of MLC flash had been considered approximately 1000times or more higher than that of SLC flash, recent research conducted on Google's data center shows that it is much lower than such expectation. Based on the research, we devised In Drive Data Duplication (IDDD) scheme that efficiently exploit MLC flash's sufficient capacity to improve its data reliability without structural complexity increment using SSD intrinsic firmware layer, and showed the data reliability expectation of MLC flash could be significantly higher than that of SLC flash from measured and calculated error rates. Even though RBER of SLC flash was lower than that of MLC flash in 44 out of 48 cases we studied, applying IDDD scheme, RBER of MLC flash was became lower than that of SLC in all 48 cases and uncorrectable bit error rate (UBER) of MLC flash was became lower than that of SLC flash in 45 out of 48 cases.

A Comparative Study on the Legal System of Building a Rooftop Gardening between Korea and China (한국과 중국의 옥상녹화 제도 비교연구)

  • Zhao, Hong-Xia;Kang, Tai-Ho
    • Journal of the Korean Institute of Landscape Architecture
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    • v.39 no.4
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    • pp.11-17
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    • 2011
  • This study focused on the regulations and support system of green rooftop landscaping between Korea and China. Our research found out regulations and support system to review the supplement point to understand the present state of green rooftop landscaping in the two countries. We aimed to provide basic legal information for the development of green rooftop landscaping regulations. Also, a management plan guide and after-evaluation guide were suggested. First, roof load safety is the foremost factor for the structure of green rooftop landscaping. It includes not only considering the weight of construction materials, but also accurately calculating weight of rain, snow and the rooftop's capacity for people when the rooftop is designed. Second, the appropriate waterproof and root material should be selected basing on climatic conditions. Third, a maintenance and management plan needs to be established to regularly check the plant, facilities, soil and to maintain them. Fourth, the criteria of quality inspection are waterproof and root resistant material, and the growth and development of plants. Waterproof and root resistant materials are a very important part of rooftop greening, so they must be strictly inspected after construction. Fifth, the support system of rooftop greening should be continuously improved. The choice of the object and the amount of support should be strictly stipulated so that the construction of rooftop is promoted when volunteers do rooftop greening.