• International Journal of Naval Architecture and Ocean Engineering
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• 제7권2호
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• pp.426-434
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• 2015

In this paper we proposed a dada-aided Doppler estimation method for underwater acoustic communication. The training sequence is non-dedicate, hence it can be designed for Doppler estimation as well as channel equalization. We assume the channel has been equalized and consider only flat-fading channel. First, based on the training symbols the theoretical received sequence is composed. Next the least square principle is applied to build the objective function, which minimizes the error between the composed and the actual received signal. Then an iterative approach is applied to solve the least square problem. The proposed approach involves an outer loop and inner loop, which resolve the channel gain and Doppler coefficient, respectively. The theoretical performance bound, i.e. the Cramer-Rao Lower Bound (CRLB) of estimation is also derived. Computer simulations results show that the proposed algorithm achieves the CRLB in medium to high SNR cases.

• 대한조선학회논문집
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• 제44권4호
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• pp.408-416
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• 2007

This paper summarizes an experimental study on the marine propeller BPF noise. The main objective of this study is to show the worthiness of the noise measurement at the MOERI middle size cavitation tunnel and to acquire useful propeller noise data. Background noise of MOERI(Maritime and Ocean Engineering Research Institute) cavitation tunnel is experimentally analyzed. Experiment carried out in the MOERI cavitation tunnel with wake screen or dummy body, which is simulated the wake. Propeller BPF noise is measured under various operating conditions. In order to secure the reliance of measured propeller noise dada, background noise of each operating conditions are measured and analyzed. The noise characteristics are analyzed according to the operating condition.

• 한국간호교육학회지
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• 제12권2호
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• pp.229-237
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• 2006

Purpose: The purpose of this study was to investigate the influencing factors of interpersonal relationship in nursing college students for effective learning ability and teaching strategy. Method: In order to get the data by self-questionnaire, 166 subjects were selected. The instruments for this study were Preceptual Orientation Scale, Self-Efficacy Scale, Narcissistic Personality Disorder Scale, and Interpersonal Relationship Scale. The dada was analyzed by percentage, mean, standard deviation, t-test, one-way ANOVA, Scheffe' test, Pearson's correlation coefficient and Stepwise multiple regression using SPSS 12.0 program. Result: The main factors that affect interpersonal relationship were self-perception and social-efficacy. These variables were account for 37.9% of interpersonal relationship. The significant influencing factors on interpersonal relationship were self-perception, social-efficacy. Conclusion: It is necessary to develop a strategy to get positive perceptual orientation and successful interpersonal relationship for nursing college students by further studies with small group program for the best result.

• 정보처리학회논문지A
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• 제9A권1호
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• pp.93-98
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• 2002

본 논문에서는 하드디스크 드라이브 읽기 채널용 아날로그/디지털 변환기를 설계하였다. 본 회로는 고속 저에러율 비교 동작이 가능한 빠른 regenerative autozero 비교기에 기반을 두고 있고, 아키텍쳐에 Double Speed Dual ADC(DADA) 방식을 사용하여 전체 A/D 변환기의 속도를 효과적으로 향상시켰다. 또한 autozero 구조에 적합한 새로운 타입의 thermometer-to-binary 디코더를 사용하여 글리치를 제거하였고 기존의 구조를 보다 최적화시켰다. 이 ADC는 6-bit, 해상도, msample/s 최대 변환속도로 설계되었으며, 390mW 전력 소모와 한 클럭주기의 latency를 가진다. 설계에 0.65m CMOS 공정을 사용하였다.

• 아시안잔디학회지
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• 제7권1호
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• pp.5-12
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• 1993

This experiment was conducted to study on the morphological change and growth retardation of Korean Lawograss (Zoysia japonica Steud.) under various shading degrees. Dada of plant height, No. of tiller, No. of stolon, No. of rhizome and fresh weight were measured on the l47days after transplanting in 1991. The results are summarized as follows. Plant height was increased at 30% shading degree or over, Maximum plant height was observed at 60% shadeing degree which was 24.2 cm. while full sunlight(control) was most shorted as 10.1 cm. Plant height rapidly was increased as to shading degree increase. The decreasing rate was lower in tiller number and stolon number(top parts of plant) compared with the rhizome number(under ground part) was severely decreased at 30% to 60% of shading. To increase the shading degree, rhizome number was most severely decreased under shading degrees. As degree of shading increase to 30%, 60% and 90%, fresh weight decrease to 66%, 44%, 22% to full sunlight, respectively. Relative growth retadation of Korean lawngrass was decreased by the order of number of rhizome, fresh weight, number of tiller, number of stolon. And these characters were highly significant accord-ing to the different shading degrees.

• 대한안전경영과학회지
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• 제18권4호
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• pp.1-9
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• 2016

In recent years, urban areas occurred several times a sinkhole. In Korea, this limestone area where the sink hole sink holes occur based on not much was seen as a very rare phenomenon. However, the occurrence of accidents in recent Subsidence and urban areas is occurring in the limestone sinkhole may yet see another one called artificial Subsidence phenomenon. Subsidence in urban areas can have various causes, such as depression groundwater level changes due to the influence of soil, underground, etc. underground utilities by anthropogenic actions. But a lot of research on natural sinkhole by geological experts continued steadily since the past Subsidence that occurred in recent years the city has become an urgent problem to formulate a countermeasure to be very concerned about the human and material damage. In this study, the city by analyzing existing research on the causes and countermeasures of Subsidence recently released look at the announced sinkhole, published statistics and cases of Subsidence data, and overseas corresponding practices in each relevant agencies and to suggest measures for local Subsidence.

• International Journal of Oral Biology
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• 제46권3호
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• pp.146-153
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• 2021

Accurate identification of microbes facilitates the prediction, prevention, and treatment of human diseases. To increase the accuracy of microbiome data analysis, a long region of the 16S rRNA is commonly sequenced via paired-end sequencing. In paired-end sequencing, a sufficient length of overlapping region is required for effective joining of the reads, and high-quality sequencing reads are needed at the overlapping region. Trimming sequences at the reads distal to a point where sequencing quality drops below a specific threshold enhance the joining process. In this study, we examined the effect of trimming conditions on the number of reads that remained after quality control and chimera removal in the Illumina paired-end reads of the V3-V4 hypervariable region. We also examined the alpha diversity and taxa assigned by each trimming condition. Optimum quality trimming increased the number of good reads and assigned more number of operational taxonomy units. The pre-analysis trimming step has a great influence on further microbiome analysis, and optimized trimming conditions should be applied for Divisive Amplicon Denoising Algorithm 2 analysis in QIIME2 platform.

• 한국인터넷방송통신학회논문지
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• 제16권6호
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• pp.15-23
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• 2016

본 논문에서는 오픈 환경에서 4G 보안 모델에 대한 연구이다. 4G 네트워크는 여전히 많은 보안 문제를 가지고 있고 전문가가 주시해야할 많은 문제들이 존재한다. 본 논문에서는 기대하지 못한 서비스를 일으키는 많은 보안 위험에 대해서 알아본다. 4G는 IP 기반과 이종 네트워크로 이루어져 있어 많은 문제를 일으키는 주된 요인이다. 본 연구에서는 4G 표준안에서 보안 문제와 취약성에 대해서 다루고 있다. 또한 WiMax 와 3GPP LTE구조에서 수행될 수 있는 여러개의 구조에 본 연구에서 제공되는 문제점과 취약성에 대해서 테스트를 하였다. 마지막으로 본 연구에서는 미래취약성에 대한 잠재적인 영역과 경고 주의가 있는 4G 평가 영역에 대해서도 다루고 있다 이 연구를 4G 네트워크 취약성에 대한 문제에 적용시켜 보다 좋은 네트워크 구조를 개발하면 학습도 보다 빠르게 이루어져 빅데이터 분석에 유용하다.

• 지질공학
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• 제19권3호
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• pp.261-268
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• 2009

터널 굴착 중 수행되는 계측은 구성 지반의 거동을 가시화하여 안정성을 평가할 수 있는 중요한 정보를 제공한다. 일반적으로 계측은 터널 굴착면 형성 초기에 집중적으로 수행되며, 시간이 경과할수록 계측횟수를 줄여 나간다. 하지만 이러한 계측 기준 및 관리 지침은 획일적이며 뚜렷한 정량적 기준이 부족한 실정이다. 본 연구에서는 굴착 초기 발생하는 변위의 안정화 시점의 정량적 판단과 안정화 이후의 미세한 변위 변동 특성 분석 및 이상거동 평가를 위해 통계 관리도 기법을 적용하였다. 계측변위에 대한 이동범위(MR) 관리도 및 누적합(CUSUM) 관리도를 작성하여 변위 평가 가능성을 검토하였다.

• 디자인학연구
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• 제11권2호
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• pp.105-114
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• 1998

20세기초 전통적인 타이포그래피의 양식의 틀을 깨고 획기적인 타이포그래피의 표현양식을 창출한 선구적인 타이포그래퍼 들은 기욤 아폴리네르와 필리포 말네티의 작품들은 같은 시대의 같은 문화적 배경에서 태어난 타이포그래피 라고 할지라도 시각적 관점과 표현 유형의 차이가 있음에도 불구하고 그간의 연구들을 통해 볼 때, 동일한 유형, 즉‘회화적 타이포’,‘표현주의 적 타이포’로 간주되어져 왔다. 따라서 아폴리네르와 마리네티의 타이포그래피의 형성 배경과 작품을 비교, 분석하여 현대 타이포그래피 형상에 끼친 영향과 의의를 재조명해 보았다. 구상적 표현과 추상적 표현이라는 큰 차이점 이외에도 타이포그래피 표현 소재와 표현방법, 지면구성, 구문의 파괴, 문장의 해체 여부에서도 특징을 발견하였으며, 1900년대 중반과 후반에 걸쳐 구상적 표현에는 브래버리 탐슨과 허브 루발린으로 추상적 표현에는 피에트 츠바르트와 네빌 브로디로 확실히 구분되어 이어지고 있음을 발견할 수 있었다.