• Journal of Korean Foot and Ankle Society
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• v.24 no.4
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• pp.129-134
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• 2020

Purpose: This study compared the results of proximal and distal chevron osteotomy in patients with severe hallux valgus. Several recent studies have shown that the indications for distal metatarsal osteotomy with a distal soft-tissue procedure could be extended to include severe hallux valgus. Materials and Methods: This study analyzed 127 severe hallux valgus surgeries. Of these, 76 patients (76 feet) were excluded for lack of adequate follow-up and additional procedures (Akin procedure), leaving 51 patients (51 feet) in the study. The mean age of the patients was 58 years (21~83 years), and the mean follow-up duration was 18 months (12~32 months). The patients were divided into two groups. Group 1 underwent distal chevron osteotomy, and group 2 underwent proximal chevron osteotomy performed sequentially by a single surgeon. The patients were interviewed for the American Orthopaedic Foot and Ankle Society (AOFAS) score before and one year after surgery. The anteroposterior weight-bearing radiography of the foot was taken before and one year after surgery. Results: There were no significant differences in pain and function after one year in either group. Both groups experienced significant pain reduction and an increase in the AOFAS score. Significant improvement of the hallux valgus and intermetatarsal angle corrections was observed in both groups, and the sesamoid position was similar in each group. More improvement in radiographic correction of intermetatarsal angle was noted in group 2. Both procedures gave similar good clinical and radiological outcomes. Conclusion: This study suggests that a distal chevron osteotomy with a distal soft-tissue procedure is as effective and reliable a means of correcting severe hallux valgus as a proximal chevron osteotomy with a distal soft-tissue procedure.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.1207-1214
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• 2021

In thisletter, we developed technology which can exclude effect of cloudsto perform remote waterbody detection based on Sentinel-2 optical satellite imagery to calculate the area of ungauged reservoirs and applied to the Hwanggang dam reservoir, a representative ungauged reservoir, to verify usability. The remote waterbody detection technology calculates the cloud blocking ratio by comparing the cloud boundary in the Sentinel-2 imagery and the reservoir boundary first. Next, itselects data whose cloud blocking ratio does not exceed a specific value and calculates NDWI (Normalized Difference Water Index) with selected imagery. In last, it calculatesthe area of the reservoir by counting the number of grids which have NDWI value considered as waterbody within the boundary of the target reservoir and correcting with cloud blocking ratio. To determine cloud blocking ratio threshold forselecting image, we performed the area calculation of Hwanggang dam reservoir from July 2018 to October 2021. As a result, when the cloud blocking ratio threshold wasset 10%, we confirmed that the result with large error due to clouds were filtered well and obtained 114 results that can show changes in Hwanggang dam reservoir area among 220 images.

• Ecology and Resilient Infrastructure
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• v.8 no.2
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• pp.88-96
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• 2021

In surface image velocimetry, a wide area of a river is photographed at an angle to measure its velocity, inevitably causing image distortion. Although a distorted image can be corrected into an orthogonal image by using 2D projective coordinate transformation and considering reference points on the same plane as the water surface, this method is limited by the uncertainty of changes in the water level in the event of a flood. Therefore, in this study, we developed a tilt image correction technique that corrects distortions in oblique images without resetting the reference points while coping with changes in the water level using the geometric relationship between the coordinates of the reference points set at a high position the camera, and the vertical distance between the water surface and the camera. Furthermore, we developed a distortion correction method to verify the corrected image, wherein we conducted a full-scale river experiment to verify the reference point transformation equation and measure the surface velocity. Based on the verification results, the proposed tilt image correction method was found to be over 97% accurate, whereas the experiment result of the surface velocity differed by approximately 4% as compared to the results calculated using the proposed method, thereby indicating high accuracy. Application of the proposed method to an image-based fixed automatic discharge measurement system can improve the accuracy of discharge measurement in the event of a flood when the water level changes rapidly.

• Journal of Cadastre & Land InformatiX
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• v.48 no.2
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• pp.109-119
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• 2018

Point of interest (POI) of the city is a special place that has what importance to the user. For example, it is such landmark, restaurants, museums, hotels, and theaters. Because of its role in the social and economic life of us, these have attracted a lot of interest in location-based applications such as social networks and online map. However, while it can easily be obtained through the Web, the basic information of POI such as geographic location, another effort is required to obtain detailed information such as Wi-Fi, accepting credit cards, opening hours, romper room and the assessment and evaluation of other users. To solve these problems, a new method for correcting position error is required to link location-based social network service (LBSNS) data and POIs. This paper attempts to propose a position error correction method of POI and LBSNS data to enrich POI information from the vast information that is accumulated in LBSNS. Through this study, we can overcome the limitation of individual POI information via the information fusion method of LBSNS and POI, and we have discovered the possibility to be able to provide additional information which users need. As a result, we expect to be able to collect a variety of POI information quickly.

• Journal of Science Education
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• v.44 no.3
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• pp.289-299
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• 2020

In this study, the definition, the level of difficulty, and the certainty of the understanding of 113 astronomy terminologies from 2009 revised middle school geoscience textbooks were examined. And through further interviews, the types of students' misconceptions about astronomy terminologies and their representative terms - examples of misconceptions were analyzed. The definitions of the terms presented by the students were largely classified as correct, low-level, and incorrect understanding. And low-level understanding was subdivided into high-level definition descriptions, undifferentiated concepts, and incorrect answers were subdivided into interference by scientific misconception and lack of prior knowledge. Given that the misconceptions due to terminologies can be distinguished from the prior misconception, the misconceptions due to terminologies can be effectively prevented by changing the term itself. In addition, students were aware of the advantages and disadvantages of metaphorical terms, and the recognition of their level of understanding is expected to be a good starting point considering that recognizing their own misconceptions is the first step in correcting them. Terminologies in science education is always an important subject of discussions, striving to select the right term according to the times, and scientific terms may change. It is expected that the results of this study will be the basis for discussions on the modification of terms.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.591-598
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• 2021

One of the requirements of metro trains is to stop with precision to ensure that the train can stop precisely at the designated location on the platform. If this is not satisfied, interference with the screen door occurs, causing inconvenience to passengers and delays in operation. In the case of an automatic operated train, the current position is determined by the current speed information of the train, and control is performed by issuing an acceleration/deceleration command. Therefore, accurate control becomes impossible if the error of the speed information is large. In metro railroads, a Precision Stop Marker (PSM) is used to correct the position error, so that the error of stop control can be reduced by correcting the position error at a specific point. On the other hand, because the PSM itself has only position information, it does not compensate for the speed error. This paper proposes a method for performing in-place stop control by estimating the speed with the PSM progress information. The speed can be estimated when the train is operated at a constant deceleration speed, and the target deceleration can be obtained to perform stop control. The feasibility and excellence of the proposed method are shown through a numerical simulation.

• 한국사회정책
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• v.23 no.2
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• pp.113-139
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• 2016

This article tries to compare exchange relations between welfare and dictatorship in the East Germany and the North Korea. Unlike capitalist welfare aiming at correcting market results socialist welfare has been proposed to satisfy people's basic needs, but it had operated as instrument of dictatorship. Relation between welfare and dictatorship could be distinguished as hard exchange and soft one in line with social construction of welfare. Welfare-dictatorship relation in East Germany had developed from its formation(1949-1970s), crisis(1980s) and dissolution(1989-1990). There had established hard exchange relation in which the legitimacy of dominance had debted to welfare as social rights. While crisis of the exchange relation had been modest in a form of insufficient supply of consumption goods, it was one of the elements of collapse of dictatorship, leading to the unification with West Germany. The journey of the exchange relation in North Korea can be characterized by its formation(1948-1980), crisis(1990s-2000s), and transformation(2010s). Unlike East Germany, welfare was socially constructed as gift form the ruler to the ruled, which made the combination of welfare and dictatorship loosely coupled. Although economic crisis was severe compared to East German one the rulers have succeeded maintaining dictatorial dominance by creating dual exchange relation. They separated core group and subordinated one supporting the former at the expense of the latter. They blocked out most of the people from soft exchange relation making bad use of muddling-through life style dependent on market activities. This strategy led to a 'dictatorship neutral welfare extinction'. Taking the high degree of institutionalization of newly establishing welfare-dictatorship relation into account, lives of most people are hardly expected to be improved by gift by their rulers even if North Korean economy will recover in the future.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.3
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• pp.179-186
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• 2021

In general, the daily safety inspection activities, which investigate damages in structures and measures the size of the damage, have been relied heavily on the visual inspection so far. Since the probe of the condition and performance of facilities by such personnel is often dependent on the subjective judgment of the investigator, the consistency and repeatability of the probing results may reduce. Particularly, damage located in a difficult-to-reach place depends mainly on experience with the naked eye, and an unsafe method using a ladder has mainly applied when necessary. Therefore, in this study, we tried to propose a way of using images that can reduce the deviation between safety inspection investigators, enhance objectivity, and improve the safety of workers. In this study, we have applied homographic transformation as a method of correcting the image. As a result of analyzing the size of the damage in the corrected image of the test subject, it confirms that the accuracy of measuring the magnitude of the damage can satisfy the target levels of 5.0mm and 0.005m², the target accuracy levels. As a result of the field verification test to which the proposed image correction technique applied, the coefficient of variation of the crack length in the structure decreased from 5.4~7.0% to 0.072~0.12%, and that of the damaged area from 10.9% to 1.6%. It confirms that the measurement accuracy is improved. Therefore, it is expected that this study on the image utilization technique in safety inspection activities can increase the accuracy of damage measurement and improve the reliability of the safety inspection reports and exterior survey drawings.

• Journal of the Korean Applied Science and Technology
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• v.38 no.1
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• pp.60-74
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• 2021

The purpose of this research was to determine the degree of awareness of early symptoms of stroke and myocardial infarction in adults diagnosed with hypertension and diabetes, and to analyze factors related to unawareness. Raw data from the 2017 Community Health Survey were utilized. A total 12,277 adults older than 40 years were included in analysis finally. The early symptom awareness rates of stroke and myocardial infarction were 53.6% and 46.8%, respectively. Logistic analysis was performed to assess factors associated with unawareness of early symptom of stroke and myocardial infarction. After correcting for socio-demographic variables, education for the management of hypertension, recognition of blood pressure level and HbA1c level were significantly related to stroke early symptom unawareness on multivariate analysis. (Education for the management of hypertension, recognition of blood pressure level and HbA1c level were significantly related to the unawareness of early stroke symptoms even after socio-demographic variables were corrected in multivariate analysis.) Recognition of blood pressure level and HbA1c level were also significantly associated with unawareness of early symptoms of myocardial infarction. Therefore, it is required to interventions and strategies to improve the level of awareness of early symptoms of cardio-cerebrovascular disease, such as accelerating promotion and strengthening education for high-risk groups who must manage both hypertension and diabetes.

• The Journal of Engineering Geology
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• v.31 no.2
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• pp.135-148
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• 2021

Ground subsidence risk ratings obtained from the site investigation during pre-excavation stages could be changed depending on the parameters revealed during construction activities. A method of correcting the pre-excavation ground subsidence risk ratings based on the site conditions observed in the field is suggested in this study. The elevation of groundwater table during the excavation may be different from the predicted value depending on the application of waterproofing methods and construction conditions. The drastic drawdown of groundwater table during the excavation could cause ground subsidence due to soil volume decrease related to consolidation or compression of the ground, whereas the rising of groundwater table caused by the intense rainfall may result in a high potential for ground subsidence due to heaving or boiling of the excavation bottom. Excessive displacements of retaining walls or ground settlements may cause ground subsidence, which also results in a high risk of ground subsidence caused by the destruction of buried pipelines. Reevaluation of ground subsidence risk ratings is suggested considering the fluctuation of groundwater table, condition of groundwater leakage, measured ground displacements, and soil types. Finally, the ground subsidence risk rating system is improved for better evaluation by using 12 factors in 5 categories.