• Fire Science and Engineering
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• v.33 no.6
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• pp.20-27
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• 2019

In this study, a new function with higher accuracy for fire heat release rate prediction was developed. The 'αt²' curve, which is the major exponential function currently used for fire engineering calculations, must be improved to minimize the prediction gap that causes fire system engineering inefficiency and lower cost-effectiveness. The newly developed prediction function was designed to cover the initial fire stage that features rapid growth based on logistic function theory, which has a more logical background and graphical similarity compared to conventional exponential function methods for 'αt²'. The new function developed in this study showed apparently higher prediction accuracy over wider range of fire growth durations. With the progress of fire growth pattern studies, the results presented herein will contribute towards more effective fire protection engineering.

• Industry Promotion Research
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• v.5 no.4
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• pp.15-28
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• 2020

In this study, the methodology for measuring the structure of the Korean defense market and the competition status, and the characteristics of the Korean defense industry and the market are examined. To analyze the structure of the Korean defense market and the competition status, the market share, concentration ratio, and the Herfindal-Hirschman index are employed based on the annual sales of major Korean defense companies. On a basis of the result of the analysis, the suggestions for the Korean defense market to escape from the monopolistic market to be a competitive geographical market are presented. To present the suggestions, markets that have a similarity with the dense market are analyzed. The government's support policy, the selection of the companies led by the government, and the cost of the military are suggested for the defense market on a basis of analyzing similar markets. With the suggestions, when the government pursues the policies, the defense market sticking to principles and fairness is created and the efficiency of the companies operation is achieved, by enhancing the structure of the market fundamentally and the development of the policies in the industry's perspective.

• Steel and Composite Structures
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• v.18 no.4
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• pp.853-871
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• 2015

Up to now, Japan has more than 200 corrugated steel web composite beam bridges which are under construction and have been constructed, and China has more than 30 corrugated steel web composite beam bridges. The bridge type includes the simply supported beam, continuous beam, continuous rigid frame and cable stayed bridge etc. The section form has developed to the single box and multi-cell box girder from the original single box and single chamber. From the stress performance and cost saving, the span range of 50~150 m is the most competitive. At present, the design mostly adopts the computational analytical method combining the spatial bar system model, plane beam grillage model and solid model. However, the spatial bar system model is short of the refinement analysis on the space effect, such as the shear lag effect, effective distribution width problem, and eccentric load factor problem etc. Due to the similarity of the plane beam grillage method in the equivalence principle, it cannot accurately reflect the shearing stress distribution and local stress of the top and bottom plates of the box type composite beam. The solid model is very difficult to combine with the overall calculation. Moreover, the spatial grid model can achieve the refinement analysis, with the integrity of the analysis and the comprehensiveness of the stress checking calculation, and can make up the deficiency of the analytical method currently. Through the example verification of the solid model and spatial grid model, it can be seen that the calculation results for the stress and the displacement of two models are almost consistent, indicating the applicability and precision of the spatial grid model.

• Korean Journal of Remote Sensing
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• v.27 no.2
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• pp.141-150
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• 2011

Precise image-to-image registration is required to process multi-sensor data together. The purpose of this paper is to develop an algorithm that register between high-resolution optical and SAR images using linear features. As a pre-processing step, initial alignment was fulfilled using manually selected tie points to remove any dislocations caused by scale difference, rotation, and translation of images. Canny edge operator was applied to both images to extract linear features. These features were used to design a cost function that finds matching points based on their similarity. Outliers having larger geometric differences than general matching points were eliminated. The remaining points were used to construct a new transformation model, which was combined the piecewise linear function with the global affine transformation, and applied to increase the accuracy of geometric correction.

• Journal of Korea Multimedia Society
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• v.13 no.2
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• pp.298-307
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• 2010

The grass is one of important components that cover the wide surfaces in the application such as game or real time simulation. Actually, it not easy to render effectively numerous grasses that grow over the wide terrain. To solve the difficulty, we must find a solution to the two contradictions in terms : quality and calculation cost. As a solution to the above-mentioned task, in this paper, we propose an efficient method to represent the natural grasses by introducing fractal theory and instancing technique. Although the existing grass representation methods make use of a simple rule of applying a basic grass model repeatedly in rendering process, on the contrary we take advantage of the basic property of fractal's self-similarity and we devise a natural representation method suited to the given environment by introducing two important growth factors such as nature of terrain and quantity of light, and finally we apply a GPU-based shader instancing technique to rendering numerous grass models in real-time.

• The KIPS Transactions:PartD
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• v.8D no.1
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• pp.88-98
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• 2001

in this paper, we imlemented design pattern retrieval system for efficient managemant and reusability of design patterns. Pattern is conssisted of property information and meta information id used for similarity measurement on classification and retrieval of patterns.Meta information od used for UML modeling of patterns. We classified design patterns with the empirical scope in addition to Gamma's basic classification. also we used E-SARM for retrieval represented UML diagram with pattern meta information, and simulated the environment so as to obtain best result on applying to retrieval of design pattern. This system is able ro resister new patterns through pattern viewer and manages these patterns with property informaiton and meta information. Thus this system supports efficient management of patterns, UML modeling, priority pattern retrieval, higher reusability and reduces pattern selection cost.

• Korean Journal of Clinical Pharmacy
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• v.30 no.2
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• pp.73-80
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• 2020

Objective: The Australian Pharmaceutical Benefits Scheme (PBS) is a national drug subsidy program. Given the similarity and comprehensiveness of the Australian PBS and the Korean National Health Insurance (NHI) data, these data are increasingly used for pharmacoepidemiological investigations, as well as international comparative studies. This study aims to introduce the various sources of publicly available PBS data and provide a practical guide to researchers conducting drug utilization studies. Methods: We searched literature and websites to detail and compare the collection, structure, components, and characteristics of each PBS data format. We identified different characteristics of the PBS data from the Korean NHI claims data which are mainly owing to their unique co-payment policies and data collection processes. In addition, the utilization and expenditure of atorvastatin, a widely used treatment for hyperlipidemia, were analyzed using two different sources of PBS data and the different results were interpreted. Results: There exist differences in when data were collected or non-subsidized uses of medicine were included among sources of PBS data. Additionally, two countries have different cost sharing methods inmedicine subsidy scheme; co-payment in Australia and co-insurance in Korea. Therefore, it should be noted that prescriptions under co-payment are not included in some data sources in Australia. Conclusion: Despite several analytical challenges, open access and easy data management are the strengths of the PBS data sources. A detailed knowledge of the PBS data can ensure robust methodology and interpretation of pharmacoepidemiological investigations or international comparative studies.

• Journal of KIISE:Databases
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• v.32 no.5
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• pp.498-508
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• 2005

A shape data is used one oi most important feature for image retrieval as data to reflect meaning of image. Especially, structural feature of shape is widely studied because it represents primitive properties of shape and relation information between basic units well. However, most structural features of shape have the problem that it is not able to guarantee an efficient search time because the features are expressed as graph or tree. In order to solve this problem, we generate curvature-based morphological graph, End design key to cluster shapes from this graph. Proposed this graph have contour features and morphological features of a shape. Shape retrieval is accomplished by stages. We reduce a search space through clustering, and determine total similarity value through pattern matching of external curvature. Various experiments show that our approach reduces computational complexity and retrieval cost.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.480-488
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• 2000

Cabbage is the most important vegetables in korea. The cabbage production was based on arduous human labor. A comprehensive research for substituting the human work by machines has been performed at present. In general, cabbage is cultivated on hillside in korea. The harvested cabbage in a field and carrying it to a vehicle for transportation are very laborious work. Hand labor in cabbage transportation to the market damages the quality of cabbage and is also a cause to increase the cost of cabbage production. This study was to design and evaluate a prototype cabbage loader for deserving efficient and safe transportation of cabbage. The developed cabbage loader was a semi-tracked vehicle operated by a hydraulic system, allowing the safe transporting and the loading of cabbage in a steep field. The maximum loading capacity of the loader was 1.0 ton. By using safety devices attached to the loader, the static slopes were 34.0% and 37.4% for the left and the rear roll-over, respectively. The maximum field speed was about 6km/hr with two cabbage pallets of 750kg at a 25% inclined field. The field capacity was about 35 pallets/hr in case of picking up, carrying and unloading two cabbage pallets. The field efficiency of the loader was analyzed to be more than 8 times in comparison of the conventional human labor. The developed loader would be applied for loading and carrying the other vegetables due to the similarity of operations. The study suggested a standard approach to the design of field machines operated in a steep field.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.2
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• pp.127-135
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• 2006

We analyzed recyclability of the fuel tanks made from steel or aluminum alloy. For a comparison of the fuel tank recyclability, first we had analyzed the process of disassembly in a vehicle and evaluated its disassemblability. Then we evaluated the recyclability for reuse and withdrawal. The processes were more or less same owing to the similarity of fastening method of fuel tank and components. However, the fuel tank of the aluminum alloy was easier (about 5%) to disassembly than the fuel tank of steel. This could be attributed to the differences in weight of steel and aluminium. On light of the withdrawal and reuse, the fuel tank made up of steel needed to plate with zinc or lead due to its anti-corrosiveness. Hence, it required additional processes. In this paper, we were explaining the results of our on going research on the recyclability of fuel tanks made of steel and aluminum alloys. The differences that we found between the fuel tank made up of the aluminum alloy and steel were in their weight, recyclability, disassemblability, anticorrosive property, cost and productivity.