• ALGAE
• /
• 제23권4호
• /
• pp.317-326
• /
• 2008

Marine algal flora and community structure were investigated seasonally at three sites in Ilkwang Bay on the southern east coast of Korea from May 2007 to February 2008. Total 103 species including 10 of green algae, 17 of brown algae, 76 of red algae were collected and identified. Among these species, 21 species were found throughout the year. Ulva pertusa, Enteromorpha linza, Grateloupia lanceolata, Chondracanthus intermedia and Caulacanthus ustulatus were distributed dominantly in upper intertidal zone. By contrast, crustose coralline algae, Grateloupia spp., Chondracanthus tenellus, Prionitis cornea and Sargassum spp. occurred predominantly in middle intertidal zone. Grateloupia spp., Sargassum spp., Ecklonia cava and Ulva pertusa were dominant in lower intertidal zone. Annual mean biomass in wet weight was 478.3 g m$^{-2}$. Maximum biomass was recorded in site 1 (731.8 g m$^{-2}$), and minimum was recorded in site 3 (78.5 g m$^{-2}$). The R/P, C/P and (R + C)/P value reflecting flora characteristics were 4.47, 0.59 and 5.06, respectively. Two groups produced by cluster analysis, one including sites 1, 2 and the other including site 3, showed meaningful difference in similarity, each other. Site 3 showed the limited species composition due to inflow of fresh water and absence of solid substratum. However, there was no significant difference between site 1 and site 2. In conclusion, the number of marine algae species and biomass in Ilkwang Bay were markedly reduced comparing with the previous studies. These suggest that a solution for reconstruction of the poor marine algal vegetation is considerably demanded.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2016년도 추계학술대회 논문집
• /
• pp.120-120
• /
• 2016

Ti-6Al-4V alloy have been used for dental implant because of its excellent biocompatibility, corrosion resistance, and mechanical properties. However, the integration of such implant in bone was not in good condition to achieve improved osseointergraiton. For solving this problem, calcium phosphate (CaP) has been applied as coating materials on Ti alloy implants for hard tissue applications because its chemical similarity to the inorganic component of human bone, capability of conducting bone formation and strong affinity to the surrounding bone tissue. Various metallic elements, such as strontium (Sr), magnesium (Mg), zinc (Zn), sodium (Na), silicon (Si), silver (Ag), and yttrium (Y) are known to play an important role in the bone formation and also affect bone mineral characteristics, such as crystallinity, degradation behavior, and mechanical properties. Especially, Zn is essential for the growth of the human and Zn coating has a major impact on the improvement of corrosion resistance. Plasma electrolytic oxidation (PEO) is a promising technology to produce porous and firmly adherent inorganic Zn containing $TiO_2(Zn-TiO_2)$coatings on Ti surface, and the a mount of Zn introduced in to the coatings can be optimized by altering the electrolyte composition. In this study, corrosion behavior of Ti-6Al-4V alloy after plasma electrolytic oxidation in solutions containing Ca, P and Zn were studied by scanning electron microscopy (SEM), AC impedance, and potentiodynamic polarization test. A series of $Zn-TiO_2$ coatings are produced on Ti dental implant using PEO, with the substitution degree, respectively, at 0, 5, 10 and 20%. The potentiodynamic polarization and AC impedance tests for corrosion behaviors were carried out in 0.9% NaCl solution at similar body temperature using a potentiostat with a scan rate of 1.67mV/s and potential range from -1500mV to +2000mV. Also, AC impedance was performed at frequencies ranging from 10MHz to 100kHz for corrosion resistance.

• 산업경영시스템학회지
• /
• 제40권4호
• /
• pp.112-119
• /
• 2017

Selecting suppliers in the global supply chain is the very difficult and complicated decision making problem particularly due to the various types of supply risk in addition to the uncertain performance of the potential suppliers. This paper proposes a multi-phase decision making model for supplier selection under supply risks in global supply chains. In the first phase, the model suggests supplier selection solutions suitable to a given condition of decision making using a rule-based expert system. The expert system consists of a knowledge base of supplier selection solutions and an "if-then" rule-based inference engine. The knowledge base contains information about options and their consistency for seven characteristics of 20 supplier selection solutions chosen from articles published in SCIE journals since 2010. In the second phase, the model computes the potential suppliers' general performance indices using a technique for order preference by similarity to ideal solution (TOPSIS) based on their scores obtained by applying the suggested solutions. In the third phase, the model computes their risk indices using a TOPSIS based on their historical and predicted scores obtained by applying a risk evaluation algorithm. The evaluation algorithm deals with seven types of supply risk that significantly affect supplier's performance and eventually influence buyer's production plan. In the fourth phase, the model selects Pareto optimal suppliers based on their general performance and risk indices. An example demonstrates the implementation of the proposed model. The proposed model provides supply chain managers with a practical tool to effectively select best suppliers while considering supply risks as well as the general performance.

• 한국통신학회논문지
• /
• 제35권9B호
• /
• pp.1259-1265
• /
• 2010

최근, 인터넷의 발달로 인해 온라인 사회연결망이 증가하고 있으며 이 중 블로그 서비스가 대표적이다. 본 논문에서는 블로그 연결망을 분석하기 위한 방법론을 제시하며, 대용량의 연결망 데이터를 안정적으로 분산 처리할 수 있는 방안을 제시한다. 우선, 각 연결망 데이터의 시간 경과에 따른 행위 가중치의 값을 보정하여, 최근의 행위가 과거의 행위보다 높은 연결강도를 가질 수 있도록 한다. 둘째로, 명시적으로 연결행위를 가지지 않은 블로그의 경우 블로그의 성격을 대표할 수 있는 키워드간의 유사도를 추출하여, 묵시적으로 연결망 내에 흡수하도록한다. 따라서 이전의 방법론과는 달리 더 많은 블로그 노드 간의 연결을 분석할 수 있다. 본 논문이 제시한 블로그 연결망 분석 시스템의 설계로 기존에 제시되었던 방법론보다 약 40% 더 많은 블로그 간 연결망을 추출 할 수 있음을 보였으며, 시간의 흐름에 따른 연결강도의 변화에 대한 타당성을 입증하였다.

• 한국ITS학회 논문지
• /
• 제16권6호
• /
• pp.1-15
• /
• 2017

최근 국제적인 테러 위협이 불특정 다수를 대상으로 발생하고 있으며, 이러한 위협에서 시민을 보호하기 위한 다양한 대책이 논의 중이다. 저렴해진 센서 기술을 활용한 사전 감시 시스템에 대한 요구가 높아지고 있으나, 보행 궤적의 고유 특성 검출 및 상세 분석 연구가 미비한 실정이다. 본 연구에서는 상용화된 보행 동선 솔루션을 활용하여, 삼성역 개찰구에서 코엑스와 직접 연결되는 연결 통로 (3-6번 출구 근처) 일대의 보행 동선 궤적 조사를 수행하였다. 조사된 궤적 자료를 바탕으로, 궤적 자료의 정규화 기법, Clustering 방법을 중심으로 보행 궤적을 유형화하고 배회 동선을 추출하는 분석 방법론을 제시하였다. 분석 결과, 동일 군집내에서 유사성이 크게 떨어지는 보행 궤적의 검출 가능성을 검증하였다.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
• /
• pp.277-282
• /
• 2006

It is well known that Kalman filtering is an optimal real-time data fusion method for GPS/INS integration. However, it has some limitations in terms of stability, adaptability and observability. A Kalman filter can perform optimally only when its dynamic model is correctly defined and the noise statistics for the measurement and process are completely known. It is found that estimated Kalman filter states could be influenced by several factors, including vehicle dynamic variations, filter tuning results, and environment changes, etc., which are difficult to model. Neural networks can map input-output relationships without apriori knowledge about them; hence a proper designed neural network is capable of learning and extracting these complex relationships with enough training. This paper presents a GPS/INS integrated system that combines Kalman filtering and neural network algorithms to improve navigation solutions during GPS outages. An Extended Kalman filter estimates INS measurement errors, plus position, velocity and attitude errors etc. Kalman filter states, and gives precise navigation solutions while GPS signals are available. At the same time, a multi-layer neural network is trained to map the vehicle dynamics with corresponding Kalman filter states, at the same rate of measurement update. After the output of the neural network meets a similarity threshold, it can be used to correct INS measurements when no GPS measurements are available. Selecting suitable inputs and outputs of the neural network is critical for this hybrid method. Detailed analysis unveils that some Kalman filter states are highly correlated with vehicle dynamic variations. The filter states that heavily impact system navigation solutions are selected as the neural network outputs. The principle of this hybrid method and the neural network design are presented. Field test data are processed to evaluate the performance of the proposed method.

• 토지주택연구
• /
• 제11권1호
• /
• pp.109-116
• /
• 2020

This study aims to establish an approach to assess urban flood vulnerability by identifying social characteristics such as the road transportation and the vulnerable groups. Assessment procedures comprise three steps as: (1) composing the assessment criteria to reflect the urban characteristics; (2) calculating the weight; and (3) evaluating the vulnerability. The criteria were adopted by Delphi survey technique. Four criteria as land cover, residents, vulnerable areas, and disaster response were adopted in the current study. To determine the weight set of criteria, subjective and objective methods were combined. The weight set was determined using the combined method which reflects the Delphi method and Entropy analysis. In the process of data-based construction, GIS tools wwere used to extract administrative unit materials such as land cover, road status, and slope. Data on population and other social criteria were collected through the National Statistical Office and the Seoul Metropolitan statistical data. TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) technique, which uses materials from cell units in order to rank the closest distance to the best case and the farthest distance from the worst case by calculating the distances to the area of assessment, was applied to assess. The study area was the Dorimcheon basin, a flood special treatment area of Seoul city. The results from the current study indicates that the established urban flood vulnerability assessment approach is able to predict the inherent vulnerable factors in urban regions and to propose the area of priority control.

• 한국유기농업학회지
• /
• 제7권1호
• /
• pp.137-146
• /
• 1998

수종의 근권세균류를 시설토양에서 분리한 후 육묘용토에 혼입처리하여 식물생장촉진효과를 측정하였다. 시설토양에서 총 125주의 단일균구를 1차적으로 순수분리하였으며, 고추에서 발생하는 위조병원균, 입고병원균, 및 묘잘록병원균 등에 대하여 항균작용이 우수한 4주의 근권세균을 최종적으로 분리하였다. 항균작용이 가장 높았던 균주로는 RB 109로서 위조병원균에 대해서는 66.0%, 입고병원균에 대해서는 65.0%, 묘잘록병원균에 대해서는 66.1% 정도의 항균작용을 나타내 전반적으로 60% 이상의 길항작용을 갖는 것으로 보였다. 길항성 균주 RB 109의 배양액을 육묘용토에 혼입처리시 고추 유묘의 초기생장이 촉진되었다. 길항성 세균 RB 109를 동정한 결과 Pseudomonas sp.와 82% 정도 유사한 균주로 동정되어 Pseudomonas sp. RB 109로 명명하였다.

• 방사선산업학회지
• /
• 제4권4호
• /
• pp.307-312
• /
• 2010

Plants have evolved physiological, biochemical and metabolic mechanisms to increase their survival under the adverse conditions. This present study has been performed to select salt-tolerant rice mutant lines through in vivo and in vitro mutagenesis with gamma-rays. For the selection of the salt-tolerant rice mutants, we conducted three times of selection procedure using 1,500 gamma ray mutant lines resulted from an embryo culture of the original rice cv. Dongan (wild-type, WT): first, selection in the a nutrient solution with 171 mM NaCl; second, selection under in vitro condition with 171 mM NaCl; and third, selection in a reclaimed saline land. Based on a growth comparison of the entries, out of the mutant lines, two putative 2 salt tolerant (ST) rice mutant lines, ST-87 and ST-301, were finally selected. The survival rate of the WT, ST-87 and ST-301 were 36.6%, 60% and 66.3% after 7 days in 171 mM NaCl treatment, respectively. The WT and two salt tolerant mutant lines were used to analyze their genetic variations. A total of 21 EcoRI and Msel primer combinations were used to analyze the genetic relationship of among the two salt-tolerant lines and the WT using the ABI3130 capillary electrophoresis system. In the AFLP analysis, a total of 1469 bands were produced by the 21 primer combinations, and 700 (47.6%) of them were identified as having polymorphism. The genetic similarity coefficients were ranged from 0.52 between the ST-87 and WT to 0.24 between the ST-301 and the WT. These rice mutant lines will be used as a control plot for physiological analysis and genetic research on salt tolerance.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2016년도 학술발표회
• /
• pp.600-600
• /
• 2016

기후변화로 인한 가뭄 및 홍수 등의 이상 현상은 유역의 수자원에 미치는 영향이 크기 때문에 이에 대한 예측 및 적응방안을 마련하는 부분이 대두되고 있다. 따라서 본 연구에서는 유역의 수자원 관리를 위하여 단위유역에서의 수자원 취약성을 평가하고자 하였다. 평가 지표는 기후 및 사회 경제 환경적 측면을 고려하여 선정하였으며, 취약성 정의에 따라 수량 및 수질/수생태에 대하여 각각 노출, 민감도, 적응능력으로 구성하였다. 이후 다기준 의사결정기법(Multi-criteria Decision Making, MCDM) 중 TOPSIS(Technique for Order Performance by Similarity to Ideal Solution)를 적용하여 각각의 통합 취약성을 도출하였다. 지표 자료는 2010년을 기준으로 국가 통계 자료를 통해 수집하였으며, 유출량과 증발산량 자료는 준분포형 장기유출모형인 SWAT(Soil and Water Assessment Tool) 모형의 모의 자료(2005~2014)를 활용하였다. 또한, 지표에 대한 가중치는 전문가 설문조사를 통해 산정한 주관적 가중치(Subjective weight)와 수집된 자료를 통하여 산정한 객관적 가중치(Objective weight)로 구분하여 적용하였다. 인구 및 산업의 밀집도가 높은 한강권역에 대하여 표준단위유역(평균 $145km^2$)의 취약성을 평가하였으며, 각각의 취약성 우선 순위를 확인하였다. 수량 취약성의 경우에는 경기 강원북부와 충정도 일부 지역이 높은 것으로 나타났으며, 수질/수생태는 수도권 등 비교적 하류에 위치한 지역의 취약성 순위가 좀 더 높았다. 가중치 적용 방법에 따른 공간분포의 차이는 수질/수생태 취약성이 더 크게 나타나는 것을 확인할 수 있었다.