• 대한조선학회논문집
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• 제45권6호
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• pp.669-678
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• 2008

The fatigue life of ship structure under cyclic loading condition is made up of initiation and propagation stages. In this study, crack growth test is carried out on large scale structure test specimens and fracture mechanical analysis is performed. The fatigue lives measured from fatigue tests are compared with DNV, Matsuoka and BS 5400 S-N curve. And to predict the crack initiation life, S-N curve, corresponding to crack length 20mm at welded joint, is developed based on hot spot stress range. Also crack propagation life is calculated using crack growth equation. Consequently, computed crack propagation life is compared with experiment results.

• 한국태양에너지학회 논문집
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• 제30권6호
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• pp.102-107
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• 2010

a-Si solar cell has relatively dominant drift current when compared with crystalline solar cell due to the high internal electric field. Such drift current make an impact on the PV module in the local shading. In this paper, the a-Si PV module output characteristics of shading effects was approached in terms of process condition, because of the different deposition layer of thin film lead to rising the resistance. We suggested design condition to ensure the long-term durability of the module with regard to the degradation factors such as hot spot by analyzing the module specification. The result shows a remarkable difference on module uniformity for each shading position. In addition, the unbalanced power loss due to power mismatch of each module could intensify the degradation.

• 디지털산업정보학회논문지
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• 제9권4호
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• pp.51-57
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• 2013

Research on calibration of array antenna has become a hot spot in the area of signal processing and it is necessary to obtain the phase mismatch of each antenna channel. This paper presents a new calibration method for an array antenna system. In order to calibrate the phase mismatch of each antenna channel, we used primary synchronization signal (PSS) which exists in LTE downlink frame. Primary synchronization signal (PSS) is based on a Zadoff-Chu sequence which has a good correlation characteristic. By using correlation calculation, we can extract primary synchronization signal (PSS). After extracting primary synchronization signal (PSS), we use it to calibrate and reduce the phase errors of each antenna channel. In order to verify the new array antenna calibration algorithm which is proposed in this paper, we have simulated the proposed algorithm by using MATLAB. The array antenna system consists of two antenna elements. The phase mismatch of first antenna and second antenna is calculated accurately by proposed algorithm in the experiment test. Theory analysis and MATLAB simulation results are shown to verify the calibration algorithm.

• Current Optics and Photonics
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• 제8권2호
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• pp.138-150
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• 2024

This study is essential for advancing our knowledge about the interaction between long-range high-power lasers and energetic materials, with a particular emphasis on understanding the response of a 155-mm shell under various surface irradiations, taking into account external factors such as atmospheric disturbances. The analysis addresses known limitations in understanding the use of non-realistic targets and the negligence of ambient conditions. The model employs the three-dimensional level-set method, computer-aided design (CAD)-based target design, and a message-passing interface (MPI) parallelization scheme that enables rapid calculations of the complex chemical reactions of the irradiated high explosives. Important outcomes from interaction modeling include the accurate prediction of the initiation time of ignition, transient pressure, and temperature responses with the location of the initial hot spot within the shell, and the relative magnitude of noise with and without the presence of physical ambient disturbances. The initiation time of combustion was increased by approximately a factor of two with atmospheric disturbance considered, while slower heating of the target resulted in an average temperature rise of approximately 650 K and average pressure increase of approximately 1 GPa compared to the no ambient disturbance condition. The results provide an understanding of the interaction between the high-power laser and energetic target at a long distance in an atmospheric condition.

• 농촌계획
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• 제21권4호
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• pp.35-43
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• 2015

The purpose of the research is to analyze damages of TYLCV (Tomato Yellow Leaf Curl Virus) in the context of climate changes and to find the spatial distribution of the damages and characteristics of regions. A TYLCV is generally known for a plant disease related to temperature. Its occurrence rate increases when temperature rises. This disease first occurred in 2008 and rapidly spread nationwide. Due to the spread of a TYLCV, a number of Tomato farms in Korea were damaged severely. To analyze damages of the pest in the context of climate changes, this research estimated production loss under the current situation and RCP scenarios. Additionally, Hot Spot Analysis, LISA, and Cluster analysis were conducted to find spatial distribution and properties of largely damaged regions under RCP scenarios. The results explained that additional production loss was estimated differently by regions with the same temperature rising scenario. Also, largely damaged regions are spatially clustered and factors causing large damages were different across regional cluster groups. It means that certain regions can be damaged more than others by diseases and pests. Furthermore, pest management policy should reflect the properties of each region such as climate conditions, cultivate environment and production technologies. The findings from this research can be utilized for developing rural management plans and pest protection policies.

• 보건행정학회지
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• 제23권4호
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• pp.387-396
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• 2013

Background: The purpose of this study was to analyze the association between areas of Korea Train Express (KTX) region and external medical service use in Korean society using spatial statistical model. Methods: The data which was used in this study was extracted from 2011 regional health care utilization statistics and health insurance key statistics from National Health Insurance Corporation. A total spatial units of 229 districts (si-gun-gu) were included in this study and spatial area was all parts of the country excepted Jeju, Ulleungdo island. We conducted Kruskal-Wallis test, correlation, Moran's I and hot-spot analysis. And after, ordinary linear regression, spatial lag, spatial error analysis was performed in order to find factors which were associated with external medical service use. The data was processed by SAS ver. 9.1 and Geoda095i (windows). Results: Moran's I of health insurance patients' external medical service use was 0.644. Also, population density, Seoul region, doctor factors positively associated with health insurance patients' external medical service. In contrast, average age, health care organization per 100 thousand were negatively associated with health insurance patients' external medical service use. Conclusion: The finding of this study suggested that health insurance patient's external medical service use correlated for seoul region in korea. The study results imply the need for more attention medical needs in the region (si-gun-gu unit) for health insurance patients of seoul region. It is important to adapt strategy to activation of primary health care as well as enhancing public health institution for prevent leakage of patients to other areas.

• Asian Pacific Journal of Cancer Prevention
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• 제15권3호
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• pp.1149-1154
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• 2014

Background: In Malaysia, data from the Malaysian Health Ministry showed colorectal cancer (CRC) to be the second most common type of cancer in 2007-2009, after breast cancer. The same was apparent after looking at males and females cases separately. In the present study, the Geographic Information System (GIS) was employed to describe the distribution of CRC cases in Kuala Lumpur (KL), Malaysia, according to socio-demographic factors (age, gender, ethnicity and district). Materials and Methods: This retrospective review concerned data for patients diagnosed with colorectal cancer in the years 1995 to 2011 collected from the Wilayah Persekutuan Health Office, taken from the cancer notification form (NCR-2), and patient medical records from the Surgical Department, Universiti Kebangsaan Malaysia Medical Centre (UKMMC). A total of 146 cases were analyzed. All the data collected were analysed using ArcGIS version 10.0 and SPSS version 19.0. Results: Patients aged 60 to 69 years accounted for the highest proportion of cases (34.2%) and males slightly predominated 76 (52.1%), Chinese had the highest number of registered cases at 108 (74.0%) and staging revealed most cases in the 3rd and 4th stages. Kernel density analysis showed more cases are concentrated up in the northern area of Petaling and Kuala Lumpur subdistricts. Spatial global pattern analysis by average nearest neighbour resulted in nearest neighbour ratio of 0.75, with Z-score of -5.59, p value of <0.01 and the z-score of -5.59. Spatial autocorrelation (Moran's I) showed clustering significant with p<0.01, Z score 3.14 and Moran's Index of 0.007. When mapping clusters with hotspot analysis (Getis-Ord Gi), hot and cold spots were identified. Hot spot areas fell on the northeast side of KL. Conclusions: This study demonstrated significant spatial patterns of cancer incidence in KL. Knowledge about these spatial patterns can provide useful information to policymakers in the planning of screening of CRC in the targeted population and improvement of healthcare facilities to provide better treatment for CRC patients.

• 한국환경복원기술학회지
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• 제23권3호
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• pp.81-89
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• 2020

The grid-based analysis is useful for conservation planning, species distribution study, education, and others'. On the west coast of Korea, it was high in species richness, rarity and endangered species richness. Our results also showed that coordinated species data can be applied to develop species distribution models due to the high correlation between total species richness and coordinated species 0richness. In hot spot analysis, high species richness areas are concentrated around the west coast, while species richness is relatively low in Gangwon and Gyeongnam. Endangered species and rarity were also concentrated on the west coast and islands. Through the complementary analysis, we selected areas which are efficient to protect species; protecting more species while minimizing the conservation effort. Our result demonstrated that simply protecting Baengyueong island, Gageo island and a part of Jeju island can conserve over 50% of bird species in South Korea. However, the validity of our analysis was limited by the absence of data from national parks, and Baekdudaegan protected areas as well as inconsistent capacity among field researchers.

• 한국지역지리학회지
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• 제16권5호
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• pp.590-609
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• 2010

본 연구의 목적은 연령별 인구이동의 구조와 공간적 패턴에 대한 이해를 향상시킬 수 있는 다양한 탐색적 공간 데이터 분석(Exploratory Spatial Data Analysis: ESDA) 기법들을 제시하는데 있다. ESDA 기법의 하나로 지역의 연령별 이동성향과 이동구조를 파악하기 위한 도구로 인구이동 피라미드를 고안하였다. 인구이동 피라미드는 연령별 전입, 전출, 순이동 정보를 이용하여 작성되는 그래픽 도구이다. 또한 연령별 인구이동의 공간적 패턴을 파악하기 위하여 다양한 국지적 연관성 측정 지표인 Local Moran's $I_i$, Getis-Ord's ${G_i}^*$와 이를 응용한 AMOEBA 기법을 이용하였다. 사례 분석 결과, 제시한 ESDA 기법들을 이용하여 연령별 인구이동 구조, 연령별 이동의 연관성, 연령별 순이동률의 공간 군집 패턴 등을 확인할 수 있었으며, 연령별 공간 군집 사이의 상응관계를 탐색할 수 있었다. 이러한 정보는 인구이동 현상에 대한 상세한 이해뿐만 아니라 인구이동을 유발하는 지역의 특성을 유추하는데 도움을 준다.

• 한국콘텐츠학회논문지
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• 제19권4호
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• pp.682-689
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• 2019

본 연구는 취약계층을 대상으로 건강정도를 객관적 지표인 체질량지수를 통해 비만 정도의 지역별 격차를 공간적으로 규명해보고자 한다. 따라서 체질량지수가 공간적으로 높은 값과 낮은 값을 가지는 군집패턴을 보이는 지역을 추출하고 이 지역의 특성을 분석하였다. 분석 결과, 비만인구비율의 I 통계량은 0.07, z-score은 4.39으로 나타나, 공간자기상관성을 확인하였다. z-score의 경우 최대 임계값인 2.57보다 훨씬 크게 나타났다. 이는 사회취약계층 비만율이 지역별 격차를 보이며, 이러한 격차가 공간통계적으로 유의함을 의미한다. 이러한 비만 취약지역과 양호지역에 대한 지역별 환경을 비교 분석한 결과는 취약지역의 경우 대중교통성이 좋지 않고 쉽게 이용할 수 있는 공원이 적으며 단독 다세대 주택이 밀집한 지역으로 확인되었다. 본 연구의 분석 결과는 기존 연구들이 소홀했던 사회취약계층의 건강에 대하여 공간적인 시사점을 제공한다는 점에서 의미를 지닌다.