• 대한원격탐사학회지
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• 제38권1호
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• pp.83-101
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• 2022

Accurate atmospheric correction is essential for the analysis of land surface and environmental monitoring. Aerosol optical depth (AOD) information is particularly important in atmospheric correction because the radiation attenuation by Mie scattering makes the differences between the radiation calculated at the satellite sensor and the radiation measured at the land surface. Thus, it is necessary to use high-quality AOD data for an appropriate atmospheric correction of high-resolution satellite images. In this study, we examined the Second Simulation of a Satellite Signal in the Solar Spectrum (6S)-based atmospheric correction results for the Sentinel-2 images in South Korea using raster AOD (MODIS) and single-point AOD (AERONET). The 6S result was overall agreed with the Sentinel-2 level 2 data. Moreover, using raster AOD showed better performance than using single-point AOD. The atmospheric correction using the single-point AOD yielded some inappropriate values for forest and water pixels, where as the atmospheric correction using raster AOD produced stable and natural patterns in accordance with the land cover map. Also, the Sentinel-2 normalized difference vegetation index (NDVI) after the 6S correction had similar patterns to the up scaled drone NDVI, although Sentinel-2 NDVI had relatively low values. Also, the spatial distribution of both images seemed very similar for growing and harvest seasons. Future work will be necessary to make efforts for the gap-filling of AOD data and an accurate bi-directional reflectance distribution function (BRDF) model for high-resolution atmospheric correction. These methods can help improve the land surface monitoring using the future Compact Advanced Satellite 500 in South Korea.

• Human Ecology Research
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• 제55권5호
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• pp.555-566
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• 2017

This study analyzes the practical tasks and required competency for technical designers to provide basic data on the training of domestic technical designers. The survey was applied to 21 technical designers of big vendors as well as investigated tasks, task flow, important tasks, time-consuming tasks, and required competencies. The results of the study are as follows. First, the technical designers were in charge of several brands of buyers and distributors of fashion companies, or several lines of the same brand. The main production items were cut and sewn knits. Second, the flow of task and tasks were in the order of buyer comments analysis, sloper decision to matching style, sewing specification, productive sewing method research, size specification suggestion, pattern correction comments, construction decision to matching style & fabric, sample evaluations, fit approval, business e-mail writing, specification & grading confirmation, and communication with buyer. Third, five tasks (analysis of buyer comments analysis, communication with buyer, pattern correction comments, productive sewing methods research, sample evaluation) were important and time-consuming tasks. Fourth, reeducation was required in order of sewing, pattern, English, fabric, and fitting. Fifth, competencies to be a technical designers were fitting, pattern correction, size specification & grading, construction & sewing specification, sewing terms & techniques, and communication skills. In conclusion, technical designer training should focus on technology-based instruction, such as sample evaluation, fitting, pattern correction, and productive sewing methods research of cut and sewn knits.

• Structural Engineering and Mechanics
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• 제63권1호
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• pp.77-88
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• 2017

Correction Factor Method (CFM) is one of the earliest methods for simulating the actual behavior of structure according to construction sequences and practical implementation steps of the construction process which corrects the results of the conventional analysis just by the application of correction factors. The most important advantages of CFM are the simplicity and time-efficiency of the computations in estimating the final modified forces of the beams. However, considerable inaccuracy in evaluating the internal forces of the other structural members obtained by the moment equilibrium equation in the connection joints is the biggest disadvantage of the method. This paper proposes a novel method to eliminate the aforementioned defect of CFM by using the column shortening correction factors of the CFM to modify the axial stiffness of columns. In this method, the effects of construction sequences are considered by performing a single step analysis which is more time-efficient when compared to the staged analysis especially in tall buildings with higher number of elements. In order to validate the proposed method, three structures with different properties are chosen and their behaviors are investigated by application of all four methods of: conventional one-step analysis, sequential construction analysis (SCA), CFM, and currently proposed method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권10호
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• pp.4971-4987
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• 2019

Node localization is the basic task of underwater wireless sensor networks (UWSNs). Most of the existing underwater localization methods rely on ranging accuracy. Due to the special environment conditions in the ocean, beacon nodes are difficult to deploy accurately. The narrow bandwidth and high delay of the underwater acoustic communication channel lead to large errors. In order to reduce the ranging error and improve the positioning accuracy, we propose a localization algorithm based on ranging correction and inertial coordination. The algorithm can be divided into two parts, Range Correction based Localization algorithm (RCL) and Inertial Coordination based Localization algorithm (ICL). RCL uses the geometric relationship between the node positions to correct the ranging error and obtain the exact node position. However, when the unknown node deviates from the deployment area with the movement of the water flow, it cannot communicate with enough beacon nodes in a certain period of time. In this case, the node uses ICL algorithm to combine position data with motion information of neighbor nodes to update its position. The simulation results show that the proposed algorithm greatly improves the positioning accuracy of unknown nodes compared with the existing localization methods.

• Journal of Positioning, Navigation, and Timing
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• 제7권4호
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• pp.277-284
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• 2018

The Satellite-based Augmentation System (SBAS), as a safety critical system, should be verified on an ongoing basis to ensure the adequate performance. This study proposes two methods to evaluate the performance of SBAS satellite correction. Analysis methods based on precise ephemeris and measurement were applied to present an evaluation method for SBAS satellite correction, and a test was performed based on real data. The precise ephemeris-based analysis method had no limitations on the position of the test user and showed a high precision, enabling an accurate performance analysis in various positions. Although the measurement-based analysis method has the advantage of fast data interval, it showed a relatively lower accuracy due to the effects of various error factors. Compared with the precise ephemeris-based analysis method, there was a large difference of more than 5 m at the beginning of smoothing filter, and a difference less than 50 cm when filtered for more than an hour.

• Journal of Chest Surgery
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• 제32권10호
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• pp.930-934
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• 1999

Background: The purpose of this study is to analyze the clinical results ad operative compatability by Ravitch methods with pectus excavatum. Material and Method: From 1984 to 1997, were performed Ravitch operations in 40 patients of pectus excavatum and analyzed the effects of correction and postoperative complication according to time of operation retrospectively. The group comprised 35 mem and women whose mean age was 8.9$\pm$7.9 years(between 2 to 35 years). All patients had corrected with Ravitch operation or its modified operation. Modified fixations were accomplished with K-wire in 15 patients and internal plate in 2 and the materials were removed 3 months after operation. The result of correction was estimated with the degree of changed distance between inner surface of sternal body and vertebral in 3 months after correction. Result: Postoperative complications were wound disruption in 14 patients. Estimated distances after correction ranged 0.4 cm to 4 cm. The acceptability for chest wall correction was high(6 excellent, 29 good in criteria of Humphreys). Conclusion: We concluded that the benefits of Ravitch operation were a high acceptability of patients and their family, and sufficient correction with no specific complications related operation.

• 한방안이비인후피부과학회지
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• 제26권4호
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• pp.43-50
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• 2013

Objectives : This study aims to suggest preliminary standard procedure for face lift and correction of nasolabial folds using thread-embedding (Maeseon) of Korean medicine(KM). Methods : Three KM practitioners of facial correction and rejuvenation who have over hundred case of practice participated in establishment of standard procedure. Standard procedure contains preprocessing, main procedure for correction, and solution of side effects. Results : Standard procedure is comprised of twelve processes with preprocessing and postprocessing. Preprocessing has position, disinfection, and anesthesia. Main process consists of overall structure correction, face lifting, nasolabial folds correction, and mesh making on cheek. Postprocess covers disinfection, edema prevention. Conclusions : To our knowledge, this is the first work to suggest standard procedure of facial rejuvenation using Maeseon. It would contribute to standardized practice in clinical fields and future study of revealing Maeseon's effectiveness.

• 한국안광학회지
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• 제13권2호
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• pp.37-41
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• 2008

목적: 이 증례의 목적은 흔치 않은 회선수직사위에 대한 프리즘 처방에 관한 것이다. 방법: 처방 프리즘은 사위도, 융합력, 조절기능 검사등과 같은 양안시 평가에서 수직이향운동의 파괴점의 중앙점으로 하였다. 결과: 수직 프리즘의 처방으로 비록 증상이 따르지 않은 수평사위는 변화가 있었으나 눈의 피로, 두통, 복시 등과 같은 증상은 개선 되었다. 그리고 회선사위는 프리즘 교정으로 나타나지 않았다. 결론: 이 사례의 프리즘 처방은 회선수직사위의 증상 완화에 유용하였다.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3488-3493
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• 2022

Accelerator driven subcritical systems have long been discussed as facilities which can be used for solving the nuclear waste problem. The physics of these systems is very different from conventional reactors and new techniques had to be developed for reactivity monitoring. One such technique is the Area Ratio Method which studies the response of a subcritical system upon insertion of a large number of neutron pulses. An issue associated with this technique is the spatial dependence of measured reactivity which is intrinsic to the sub criticality of the system since the reactor does not operate on the fundamental mode and measured reactivity depends on the detector position. This is generally addressed by defining Bell-Glasstone spatial correction factor. This factor upon multiplication with measured reactivity gives the correct reactivity which is independent of detector location. Monte Carlo Methods are used for evaluating these factors. This paper presents a complete three dimensional map of spatial correction factors for BRAHMMA subcritical system. In addition, the dataset obtained also helps in identifying detector locations where the correction factor is close to unity, thereby implying no correction if the detector is used at those locations.

• 한국안광학회지
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• 제17권1호
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• pp.75-81
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• 2012

목적: 양안개방형 자동굴절검사기를 이용하여 완전교정과 저교정 상태에서 실제 일어나는 조절 반응량을 측정하여 조절의 변화를 알아보고자 하였다. 방법: 20~30세($21.14{\pm}2.00$세)의 대학생 79명(남 58명, 여 21명)을 대상으로 타각적 자각적 굴절검사를 실시하여 완전교정은 시력이 1.0일 때, 저교정은 임의적으로 플러스 렌즈를 부가하여 0.8, 0.7, 0.6일 때의 조절 반응량을 5.0 m, 1.0 m, 0.50 m, 0.33 m, 0.25 m에서 측정하였다. 피검사자를 대상으로 주시거리에 따른 1.0, 0.8, 0.7, 0.6 시력 상태에서 조절 반응량의 변화를 비교 분석하였다. 결과: 우안 좌안 모두 완전교정 상태(1.0)가 저교정 상태(0.7) 보다 조절 반응량의 값이 크게 나타났다(p=0.000). 완전교정 상태가 저교정 상태(0.7) 보다 주시거리가 짧아질수록 조절 반응량의 변화가 더 크게 나타났다. 주시거리에 따른 시력과 조절 반응량의 상관관계는 거리가 짧을수록 더 낮게 조사 되었다. 결론: 장시간 근거리 작업은 조절기능에 영향을 줄 수 있으므로 저교정을 하여 눈의 안위를 편안하게 하는 것이 안정피로 증상을 해소하는데 도움이 될 것이다.