• Journal of the Korean Geographical Society
• /
• v.48 no.2
• /
• pp.184-203
• /
• 2013

This study analyzes the variability of Korean summer rainfall associated with the tropical low-frequency oscillation using long-term observation data. From the EOF analysis, the first mode showed opposite phase between the South and the North Korea with the regime shift in rainfall variability since the mid-1990s. The summer precipitation over South Korea tends to increase in southern part during strong El Ni$\tilde{n}$o where the warm sea surface temperature extends to far eastern tropical Pacific. In weak La Ni$\tilde{n}$a, the increased precipitation directly influences from the western tropical Pacific to the mid-latitude. In June, the rainfall over South Korea is positively correlated with the Indian Summer Monsoon while in July, it is negatively correlated with the Western North Pacific Summer Monsoon. In August, highly negative correlation between the rainfall over South Korea and the Indian Summer Monsoon is found.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.1
• /
• pp.89-95
• /
• 2013

This study investigates a parallel manipulator that can move over two parallel sliders and in which the end-effector of the manipulator can be adjusted arbitrarily. Through the direct and inverse kinematics of the manipulator, position equations are derived. These equations represent the relationship between the positions of the sliders and the position of the end-effector. The Jacobian matrices of the direct and inverse kinematics are obtained by these equations. By using the condition number defined from these matrices, the local performance index of the manipulator is proposed. By using the simulation results of the performance index, we find that the manipulator can smoothen movements in only one quadrant and that the distribution of the maximal performance index is affected by the ratio of the length of links and the orientation of the end-effector.

• Korean Journal of Remote Sensing
• /
• v.39 no.6_2
• /
• pp.1635-1650
• /
• 2023

Under global warming, the steadily increasing sea surface temperature (SST) severely impacts marine ecosystems,such as the productivity decrease and change in marine species distribution. Recently, the catch of Todarodes Pacificus, one of South Korea's primary marine resources, has dramatically decreased. In this study, we analyze the marine environment that affects the formation of fishing grounds of Todarodes Pacificus and develop seasonal habitat suitability index (HSI) models based on various satellite data including Geostationary Ocean Color Imager (GOCI) data to continuously manage fisheries resources over Korean exclusive economic zone. About 83% of catches are found within the range of SST of 14.11-26.16℃,sea level height of 0.56-0.82 m, chlorophyll-a concentration of 0.31-1.52 mg m^-3, and primary production of 580.96-1574.13 mg C m^-2 day^-1. The seasonal HSI models are developed using the Arithmetic Mean Model, which showed the best performance. Comparing the developed HSI value with the 2019 catch data, it is confirmed that the HSI model is valid because the fishing grounds are formed in different sea regions by season (East Sea in winter and Yellow Sea in summer) and the high HSI (> 0.6) concurrences to areas with the high catch. In addition, we identified the significant increasing trend in SST over study regions, which is highly related to the formation of fishing grounds of Todarodes Pacificus. We can expect the fishing grounds will be changed by accelerating ocean warming in the future. Continuous HSI monitoring is necessary to manage fisheries' spatial and temporal distribution.

• Journal of the Korea Concrete Institute
• /
• v.26 no.4
• /
• pp.507-515
• /
• 2014

Although the construction joints of a concrete structure are properly treated with some measures, leakage has frequently occurred. A series of tests on the bond characteristics between new and old concrete were carried out in this study, assuming that the leakage at the construction joints has certain relationship with the bond of concrete. To assess the bond characteristics under various conditions, a number of specimens were made that have an interface between new and old concrete and bond strength, flexural strength and splitting tensile strength were measured. Main test variables are type and amount of mineral admixtures, treatment method of the interface and type of waterstops. In addition, the effects of placing interval between the concrete and of the age of the strength tests were investigated. The test results showed a slightly increased bond strength when applying mineral admixtures, which can be attributed to the interface filled with the calcium silicate hydrate that is formed by pozzolanic reaction. On the other hand, the bond strength was higher when the interface was treated rough and dry, and the roughness of a waterstop affected the bond capacity of the waterstop. Also, an assessment is required that considers the type of strength test because the bond strength varied according to the test methods.

• Journal of the Korean association of regional geographers
• /
• v.5 no.1
• /
• pp.151-162
• /
• 1999

This study is a comparative analysis of sea level and 500hPa surfaces between dry year and wet year, which are selected by variability of precipitation and standardized anomalies in Korea in early autumn. While the amount of precipitation of early autumn decreases, the variability of precipitation increases rapidly reflecting the strength and weakness of Kaul Changma front and the occurrences of the typhoonic precipitation. The regional distribution of the variability of precipitation shows west-high, east-low pattern in which the east coast and the southeastern coast shows low, but high in the southwestern coast. In the anomalies distribution of sea-level and 500hPa surfaces, during dry year, the northern part of Siberia and the core area of North Pacific high shows negative anomalies, on the contrary, there were positive anomalies in wet year at the same areas. In addition, at the 500hPa level, while the Korean peninsula was located at the west of deep trough with low zonal index in dry year, the peninsula was influenced by weak trough with high zonal index showing strong zonal flow in wet year. During dry year the height of 500hPa surface is low at the north of $40^{\circ}N$, but high in wet year. In consequences, this study identified that the occurrences of dry year and wet year were influenced by the seasonal variations of the strength and the weakness of North Pacific high and Siberian high.

• Journal of KIISE:Software and Applications
• /
• v.26 no.1
• /
• pp.25-39
• /
• 1999

지리 정보 시스템에서 공간 분석을 위해 사용되는 중요한 연산인 공간 조인은 대상이 되는 공간 객체의 수가 증가함에 따라서 연산 시간이 지수적으로 증가하는 특징을 가지고 있다. 그러므로 다량의 공간 데이터에 대해서 공간 연산시간을 줄이기 위한 병렬처리가 필요하다. 이 논문에서는 비겹침 정규분할 방식의 사분트리를 이용한 공간 조인 알고리즘을 제시하고 MIMD 구조 및 공유 디스크 방식의 병렬 처리시스템에 적용하여 성능을 평가한다. 사분트리를 이용한 공간조인 방법으로서 중복 표현된 공간객체를 줄이기 위한 사분면(quadrant)의 병합 방법,영역 제한을 통해 연산 대상 객체를 줄이기 위한 사분면의 분할 방법, 그리고 병합 및 분할 방법을 혼용하여 공간 조인 연산의 숫자를 최소화하는 혼합 방법을 제시한다. 실험 평가에서는 각 방법들을 병렬 처리 시스템에 적용하여 여과단계 및 정제단계에서의 연산량과 수행 시간을 통해 성능을 비교 평가한다. 실험결과, 여과 단계에서는 분할 방법이 가장 우수했지만, 정제 단계에서는 병합 방법이 가장 우수했다. 따라서 전체적인 고려할 때 두 방법의 장점을 수용한 혼합 방법이 가장 우수한 성능을 나타냈다.

• Journal of the Korean Vacuum Society
• /
• v.3 no.2
• /
• pp.220-226
• /
• 1994

본 연구에서는 폴리에스터(PET) 필름 위에 아연을 연속적으로 진공증착하는 실험을 수행한 후 얻어진 박막의 조직 및 조성을 SEM 및 AES로 조사하였다. 박막의 X-선 회절부석 결과, 2$ heta$=36。에서 아연의(0002)면이 주피크로 나타났으며 투과전자 현미경 관찰 결가 hcprn조로 증착시 basal plane인 (0001)면에 평행한 방향으로 우선 성장한다. 대기중 노출시 증착필름은 수분 및 산소와 반응하여 매우 다공성이며 부착성이불량한 산화피막을 형성하기 때문에 1차피막형성 후에도 산화가 지속적으로 진행되 었다. 박막내 존재하는 산소의 농도는 내부로 갈수록 지수함수적으로 감소하다가 증착금속과 기판간의 계면에서 다시 증가하는 경향을 보인다. 박막의 부식 특성을 조사현 결과 균일한 산화막 형성과 더불어 수분 존재하에 아연충에 미세한 pin hole 이 공극 부분부터 형성되어 개수가 증가하며 주위로 확장되는 형태를 나타내고 있다.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.11 no.3
• /
• pp.192-197
• /
• 2003

The ‘AEIPR’(Accelerometer Established Inertial Profiling Reference) method has been applied to measure the road profile. The dynamic road profiling method using AEIPR has the advantages of cost effectiveness, measuring speed and relatively high reliability. However, it is required to improve the double integration algorithm to get the measurement results with the accuracy of hither level. In the first part of this paper, the effective double integration algorithm is suggested and the ‘Road Profiler’ software is developed on the basis of the algorithm. Road profiling tests are performed using the developed ‘Road Profiler’ system on the specially designed tracks for the durability tests and the various types of pubic roads. Test results are shown and evaluated by the international road evaluation indicies and classification.

• Journal of Advanced Marine Engineering and Technology
• /
• v.29 no.2
• /
• pp.194-201
• /
• 2005

For engineers in the industry, this study considers a reliable and practical finite element modeling technique to estimate the behavior of closed thin-walled members with spot weldings. Dynamic and static experiments confirm that the technique - modeling the spot weldings with solid elements which have the adjusted rotational freedoms and fill the welding space - Yields satisfactory results. Numerical studies on the double hat-shaped members. adopting this modeling technique. show the effect of the spot welding Pitch and the spot welding location in the flange on the stiffness of the members Using the principal stiffness and newly proposed GSPI(global stiffness performance index), we also carefully examine how the spot welding curvature, and sectional shape, etc.. synthetically influence the stiffness of a real excavator pillar in the field.

• Annual Conference of KIPS
• /
• 2020.11a
• /
• pp.41-42
• /
• 2020

전 세계적으로 코로나 바이러스가 확산되면서 언택트 시대가 되었다. 언택트 시대에서는 대부분의 대면활동이 비대면으로 전환되고 있다. 전 세계적으로 열광중인 케이팝 댄스의 대중화를 위해 우리는 비대면으로 댄스 학습이 가능한 DETR 기반 객체탐지를 사용한 댄스 자세교정 연구를 제안한다. 본 논문에서 제안한 댄스 자세교정은 객체탐지에 DETR을 적용한 방식이다. DETR은 기존 객체탐지 모델에서 앵커박스, 바운딩박스 중복처리를 제거하는 NMS같은 휴리스틱한 방법을 사용하지 않고 트랜스포머를 통해 자동으로 학습하도록 만든 모델이다. DETR로 객체탐지를 한 후 강사와 사용자의 동작유사성을 샴 뉴럴 네트워크를 통해 계산한다.