• International Journal of Naval Architecture and Ocean Engineering
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• 제6권4호
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• pp.947-964
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• 2014

Rubble mound breakwaters protect the coastal line against severe erosion caused by wave action. This study examined the performance of different sizes and properties (i.e. height of vertical wall and tetrapod size) of rubble mound breakwaters on reducing the overtopping discharge. The physical model used in this study was derived based on an actual rubble mound in Busan Yacht Harbor. This research attempts to fill the gap in practical knowledge on the combined effect of the armor roughness and vertical wall on wave overtopping in rubble mound breakwaters. The main governing parameters used in this study were the vertical wall height, variation of the tetrapod weights, initial water level elevation, and the volume of overtopping under constant wave properties. The experimental results showed that the roughness factor differed according to the tetrapod size. Furthermore, the overtopping discharge with no vertical wall was similar to that with relatively short vertical walls (${\gamma}_v=1$). Therefore, the experimental results highlight the importance of the height of the vertical wall in reducing overtopping discharge. Moreover, a large tetrapod size may allow coastal engineers to choose a shorter vertical wall to save cost, while obtaining better performance.

• 한국수산과학회지
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• 제27권5호
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• pp.594-604
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• 1994

The storm surges caused by the typhoon Brenda in 1985 were studied by analysing tidal observation data at 7 stations along the south coast of the Korean peninsula. The tidal deviation at these stations along the coast are discussed in association with meteorological data. The sea level anomalies were studied by means of the Empirical Orthogonal Function (EOF) analysis and the Fast Fourier Transform(FFT) method. From the result of EOF analysis, the temporal and spatial variations of storm surge were described by the first mode of EOF, which is $73\%$ of the total variances during the passage of typhoon Brenda. From the results of FFT spectral analysis, the peak energy of the autospectrum for surge, atmospheric pressure, and wind stress appeared in the low frequency fluctuations band. The result of FFT analysis showed that the typhoon surge was related chiefly to the atmospheric pressure change in an open bay such as Cheju and Keomundo harbor, while it was influenced mainly by the wind stress in the semi-enclosed waters of Yeosu, Chungmu and Kadukdo.

• 한국수산과학회지
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• 제29권3호
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• pp.369-385
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• 1996

가막만 식물플랑크톤에 대한 기초생산력을 산정하기 위해 해수유동모델과 생태계 모델을 이용하였다. 이를 위해 양식기간동안 양식장이 없는 조건으로 식물플랑크톤에 대한 기초생산력을 산정하였으며 그 결과는 다음과 같다. 양식장이 없는 경우로 월별 식물플랑크톤을 예측한 결과로 월별 식물플랑크톤량의 변화를 보면 6월부터 증가하기 시작하여 9월이 가장 높은 식물플랑크톤량을 보이고 9월부터 12월까지 급격히 감소하다가 그 이후 3월까지 서서히 감소하였다. 양식장이 없는 경우로 월별 식물플랑크톤에 대해 계산한 기초생산력을 보면 양식기간 동안 범위는 $0.99\~10.20gC/m^2/d$로 평균 $4.43gC/m^2/d$이였다. 월별 변동을 보면 6월부터 급격하게 증가하기 시작하여 8월에 가장 높은 생산력을 보이고 8월 이후 12월까지 급격히 감소하다가 1월 이후에 3월까지 서서히 증가하는 경향을 보였다.

• 수산해양기술연구
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• 제27권4호
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• pp.293-302
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• 1991

태풍해일의 변동양상과 특성을 파악하기 위하여, 한국 남해안의 7개 검조소의 조석관측자료와 기상자료를 사용하여 태풍 Thelma 통과기간 중 각 항에서의 추산조위와 해일을 추정하여, 시간영역별 기상 및 해면변동에 관한 EOF분석을 하고 태풍해일, 기압, 바람응력의 spectrum분석을 실시하였다. 반폐쇄성 만(여수)인 경우 바람응력이 기압보다 해일발생에 큰 영향을 미치며, 개방된 항만(제주)은 기압이 해일에 큰 역할을 하는 것으로 나타났다. 해일의 값은 13.1~91.7cm 범위로서 여수에서 최고치를 보였다. 태풍 Thelma 통과시 EOF 제 1 모드는 전체 해일변동의 63%를 차지하였고, 제 1 모드에 수반된 해일의 시간변동은 18 시간 동안 쌍봉의 peak를 가진 변동을 보였다. 제 1 모드에 대한 남해안 7개 지점에서의 해일의 공간적 변동은 여수를 중심으로 동시에 해면이 상승하였다. 남해안 4개항(부산, 충무, 여수, 제주)의 해일, 기압 및 바람응력 spectrum의 peak 에너지는 0.008-0.076cph(약 3-10시간)의 저주파수대에 밀집되어 있고, 해일의 경우 여수와 제주에서 에너지 밀도가 크게 나타났다. 기압의 에너지 변동은 탁월하지 않았으며, 바람응력은 부산, 여수, 제주에서 에너지 밀도가 잘 나타났다. 또한, 세 변동성분의 자기상관은 해일의 경우 주기적 변동을 나타내었고, 기압과 바람응력은 모두 불규칙적인 상관을 보였다.

• 한국수산과학회지
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• 제23권3호
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• pp.215-224
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• 1990

포화상태인 물질의 역학적, 수리학적 거동을 연구할 수 있는 유한요소법적 수치해석모델을 개발하여 부산 남항 인근해역의 미고결 퇴적물의 거동을 분석하였다. 하중재하에 의한 상부세립 퇴적물의 역학적 변형은 공극수의 확산에 따른 공극수압의 수리학적 변화에 크게 영향을 받는 것으로 나타났다. 하중이 일정지역에 편재되어 있을 경우 포아송효과 및 과잉공극수압의 영향에 의해 하중을 직접 받지 않는 표층부분이 융기되며, 하중경계지역에서 멀어질수록 점근적으로 증가한다. 세립점토층에 비해 높은 투수성을 갖는 하부 모래층은 공극수확산의 통로역할을 하여 과잉공극수압의 소멸을 촉진시키며, 결과적으로 상부점토층 변형의 시간적 변화에도 영향을 끼친다.

• 콘크리트학회지
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• 제10권2호
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• pp.127-135
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• 1998

프리캐스트 세그멘탈 교량의 3차원적인 선형관리를 수행할 수 있는 S/W로서 GEOCON이 개발되었다. GEOCON은 기본적으로 제작장에서 세그멘트 제작관리를 통한 선형관리를 실시하고, 그 결과로서 자동적으로 계산되는 제작선형은 가설시 선형관리에 활용된다. 본 논문에서는 실제 현장에서 나타날 수 있는 검측오차등으로 인하여 수치계산상으로는 마치 정확한 선형관리가 이루어지는 것으로 나타날 수 있는 상황들을 방지하기 위해 GEOCON에서 채택하고 있는 기술적인 특징들에 대하여 논하고 있다. 또한 실제 현장적용을 통하여 GEOCON의 효용성을 검증하였다. GEOCON을 통하여 선형관리된 부산항 배후도로 현장은 총 길이 2109m의 프리캐스트 세그멘탈 교량구간을 포함하고 있으며 고임판의 사용없이 허용 관리치 내에서 매우 정확한 선형관리가 이루어졌다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.431-438
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• 2002

Reclaimed coastal areas for the construction of ports and harbors are in general subjected to strong possibility of liquefaction. In this research, a new method for liquefaction hazard microzonation based on liquefaction settlements was developed. Severity of liquefaction hazard was defined by liquefaction settlements obtained from the method proposed by Tokimatsu and Seed. 10 coastal areas, representing typical geological and geotechnical characteristics of Korean ports and harbors, and 3 real earthquake records for site response analysis were selected. From this research, liquefaction settlement criteria is adapted as a new quantitative index for the liquefaction hazard microzonation. Liquefaction settlements were also compared with LPI (Liquefaction Potential Index), obtained from the assessment of liquefaction potential based on the modified Seed and Idriss's method. As an example, 2 and 3 dimensional liquefaction hazard microzonations of Pusan port and harbor area were mapped by overlapped liquefaction settlement contours.

• 한국항해항만학회지
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• 제36권7호
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• pp.585-590
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• 2012

On the basis of the potentials for the growth of local economy and the result of investigation of the ocean space development status, an ocean resort complex was proposed at the small harbor with a parallel beach in the east coast of Korea. As the development plan needs to reclaim the noticeable amount of coastal water area together with the applied shore facilities, it is necessary to analyze their impacts. Here, it was intended to analyze the coastal environment change such as water circulation and bottom change because of the development plan. A horizontal two-dimensional numerical model was applied to represent the combined impact of wind waves and tidal currents to sediment transport in that coastal region. Based on the result of 30 days tidal current simulations considering major four tidal components of $M_2$,$S_2$,$K_1$ and $O_1$ for the upper and lower boundaries and wind field data, bottom change was discussed. Flow velocities were not changed much at outer breakwater of Yangpo harbor. Bottom was eroded by maximum 1.7m after construction but some locations such as lee side of outer breakwater and some islets near the entrance shows isolated accretions. Although it needs more field observations for bottom change in the period of construction, the numerical calculation shows that there exist small impacts near the entrance area and coastal boundaries because of the development.

• Journal of Microbiology and Biotechnology
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• 제16권6호
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• pp.889-895
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• 2006

To investigate the antibiotic-resistant patterns and the gene types of extended-spectrum $\beta$-lactamase (ESBL)-producing Klebsiella pneumoniae, we collected 226 Klebsiella pneumoniae strains from three general hospitals with more than 500 beds in Busan, Korea from September 2004 to October 2005, The minimum inhibitory concentration (MIC) of antibiotics was measured using the Gram-negative susceptibility (GNS) cards of Vitek (Vitek system, Hazelwood Inc., MO, U.S.A.). Of the 226 K, pneumoniae isolates, 65 ESBL-producing K. pneumoniae strains were detected by the Vitek system and confirmed by the double-disk synergy test. TEM (Temoniera) type, SHV (sulfhydryl variable) type, and CTX-M (cefotaxime) type genes were detected by polymerase chain reaction. All 65 K. pneumoniae strains were resistant to ampicillin, cefazolin, cefepime, ceftriaxone, and aztreonam, and 83.0% of the organisms were resistant to ampicillin/sulbactam, 66.1% to tobramycin, 67.6% to piperacillin/tazobactam, 61.5% to ciprofloxacin, and 47.6% to trimethoprim/sulfamethoxazole, and 43.0% to gentamicin. TEM-type ESBLs (TEM-1 type, -52 type) were found in 64.6% (42 of 65) of the isolates, SHV-type ESBLs (SHV-2a type, -12 type, -28 type) in 70.7% (46 of 65) of isolates, and CTX-M-type ESBLS (CTX-M-15 type) in 45% (29 of 65) of isolates. Of the 65 ESBL-producing K. pneumoniae strains, two strains were found to harbor blaSHV-28, which were detected in Korea for the first time. Therefore, more investigation and research on SHV-28 are needed in order to prevent the ESBL type-producing K. pneumoniae from spreading resistance to oxyimino cephalosporin antibiotics.

• Journal of Microbiology
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• 제43권4호
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• pp.345-353
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• 2005

The complex ecosystem of intestinal micro flora is estimated to harbor approximately 400 different microbial species, mostly bacteria. However, studies on bacterial colonization have mostly been based on culturing methods, which only detect a small fraction of the whole microbiotic ecosystem of the gut. To clarify the initial acquisition and subsequent colonization of bacteria in an infant within the few days after birth, phylogenetic analysis was performed using 16S rDNA sequences from the DNA iso-lated from feces on the 1st, 3rd, and 6th day. 16S rDNA libraries were constructed with the amplicons of PCR conditions at 30 cycles and $50^{\circ}C$ annealing temperature. Nine independent libraries were produced by the application of three sets of primers (set A, set B, and set C) combined with three fecal samples for day 1, day 3, and day 6 of life. Approximately 220 clones ($76.7\%$) of all 325 isolated clones were characterized as known species, while other 105 clones ($32.3\%$) were characterized as unknown species. The library clone with set A universal primers amplifying 350 bp displayed increased diversity by days. Thus, set A primers were better suited for this type of molecular ecological analysis. On the first day of the life of the infant, Enterobacter, Lactococcus lactis, Leuconostoc citreum, and Streptococcus mitis were present. The largest taxonomic group was L. lactis. On the third day of the life of the infant, Enterobacter, Enterococcus faecalis, Escherichia coli, S. mitis, and Streptococcus salivarius were present. On the sixth day of the life of the infant, Citrobacter, Clostridium difficile, Enterobacter sp., Enterobacter cloacae, and E. coli were present. The largest taxonomic group was E. coli. These results showed that microbiotic diversity changes very rapidly in the few days after birth, and the acquisition of unculturable bacteria expanded rapidly after the third day.