• Journal of the Korea Concrete Institute
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• 제24권1호
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• pp.15-23
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• 2012

This paper is about proposal of a calculation method and development of an analytical program for predicting crack width and deflection in structural concrete members. The proposed method numerically calculate stresses in steel rebar using a parabola-rectangle stress-strain curve and a modified tension stiffening factor considering the effect of the cover thickness. Based on the study results, a calculation method to predict crack width and deflection in reinforced concrete flexural members is proposed utilizing effective tension area and idealized tension chord as well as effective moment-curvature relationship considering tension stiffening effect. The calculation method was applied to the test specimens available in literatures. The study results showed that the crack width and deflections predicted by the proposed method were closed to the experimentally measured data compared the current design code provisions.

• Journal of Korea Multimedia Society
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• 제12권5호
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• pp.644-652
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• 2009

New communication environments such as USN, WiBro and RFID have been realized nowadays. Thus, in order to ensure security and privacy protection, various light-weight block ciphers, e.g., mCrypton, HIGHT, SEA and PRESENT, have been proposed. The block cipher mCrypton, which is a light-weight version of Crypton, is a 64-bit block cipher with three key size options (64 bits, 96 bits, 128 bits). In this paper we show that 8-round mCrypton with 128-bit key is vulnerable to related-key rectangle attack. It is the first known cryptanalytic result on mCrypton. We first describe how to construct two related-key truncated differentials on which 7-round related-key rectangle distinguisher is based and then exploit it to attack 8-round mCrypton. This attack requires $2^{45.5}$dada and $2^{45.5}$time complexities which is faster than exhaustive key search.

• Journal of KIISE
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• 제44권1호
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• pp.71-77
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• 2017

There has been a recent spate in the usage of mobile device equipped GPS sensors, such as smart phones. This trend enables the posting of geo-tagged messages (i.e., multimedia messages with GPS locations) on social media such as Twitter and Facebook, and the volume of such spatial data is rapidly growing. However, the relationships between the location and content of messages are not always explicitly shown in such geo-tagged messages. Thus, the need arises to reorganize search results to find the relationship between keywords and the spatial distribution of messages. We find the smallest minimum bounding rectangle (MBR) that embedding k or more points in order to find the most dense rectangle of data, and it can be usefully used in the location search system. In this paper, we suggest efficient algorithms to discover a group of 2-Dimensional spatial data with a close distance, such as MBR. The efficiency of our proposed algorithms with synthetic and real data sets is confirmed experimentally.

• The KIPS Transactions:PartA
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• 제10A권6호
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• pp.643-650
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• 2003

This paper presents a new submesh allocation scheme for mesh-connected multicomputer systems. The key idea in the proposed allocation scheme is to reduce the submesh search time using classified free submesh lists (CFSL). This scheme reduces the submesh search time by classifying independent free submeshes according to their types (square, horizontal rectangle, vertical rectangle) and searching the best-fit submesh from the classified free submesh list. When no suitable submesh is found, the search can be continued by using the expansion index (El), which is stored as an attribute of each submesh, is used to form a larger submesh. Through simulation, we show that the proposed strategy improves the performance compared to previous strategies with respect to submesh search time.

• KIPS Transactions on Software and Data Engineering
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• 제2권11호
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• pp.789-794
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• 2013

A vehicle tracking system makes it possible to induce the vehicle movement path for avoiding traffic congestion and to prevent traffic accidents in advance by recognizing traffic flow, monitoring vehicles, and detecting road accidents. To track the vehicles effectively, those which appear in a sequence of video frames need to identified by extracting the features of each object in the frames. Next, the identical vehicles over the continuous frames need to be recognized through the matching among the objects' feature values. In this paper, we identify objects by binarizing the difference image between a target and a referential image, and the labelling technique. As feature values, we use the center coordinate of the minimum bounding rectangle(MBR) of the identified object and the averages of 1D FFT(fast Fourier transform) coefficients with respect to the horizontal and vertical direction of the MBR. A vehicle is tracked in such a way that the pair of objects that have the highest similarity among objects in two continuous images are regarded as an identical object. The experimental result shows that the proposed method outperforms the existing methods that use geometrical features in tracking accuracy.

• Journal of Korea Multimedia Society
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• 제6권3호
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• pp.409-418
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• 2003

Object tracking in video is one of subject that computer vision and several practical application field have interest in several years. This paper proposes real time object tracking and face region extraction method that can be applied to security and supervisory system field. For this, in limited environment that camera is fixed and there is seldom change of background image, proposed method detects position of object and traces motion using difference between input image and background image. The system creates adaptive background image and extracts pixels in object using line scan method for more stable object extraction. The real time object tracking is possible through establishment of MBR(Minimum Bounding Rectangle) using extracted pixels. Also, effectiveness for security and supervisory system is improved due to extract face region in established MBR. And through an experiment, the system shows fast real time object tracking under limited environment.

• Journal of KIISE:Databases
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• 제30권3호
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• pp.286-295
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• 2003

The shape of query windows for spatial selection queries is a rectangle in many cases. However, it can be issued for spatial selection queries with not only rectangular query widow, but also polygonal query window. Moreover, as the applications like GIS can manage much more spatial data, they can support the more various applications. Therefore it is valuable for considering about the query processing method suitable for not only rectangle query window, but also general polygonal one. It is the general state-of-the-art approach to use the plane- sweep technique as the computation algorithm in the refinement step as the spatial join queries do. However, from the observation on the characteristics of spatial data and query windows, we can find in many cases that the shape of query window is much simpler than that of spatial data. From these observations, we suggest a new refinement process approach which is suitable for this situation. Our experiments show that, if the number of vertices composing the query window is less than about 20, the new approach we suggest is superior to the state-of-the-art approach by about 20% in general cases.

• Journal of the Society of Naval Architects of Korea
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• 제51권4호
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• pp.342-348
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• 2014

In general, the forming process of the curved hull plates consists of sub tasks, such as roll bending, line heating, and triangle heating. In order to complement the automated curved hull forming system, it is necessary to develop an algorithm to classify the curved hull plates of a ship into standard shapes with respect to the techniques of forming task, such as the roll bending, the line heating, and the triangle heating. In the previous research, the classification algorithm of curved hull plates was studied only about rectangle shaped plates, and other limitations were notified. In this paper, the classification algorithm is extended to classify not only rectangle shaped plates but also arbitrary polygon hull plates. The discrete curvature can be computed by using arbitrary polygon mesh which is represented by half-edge data structure and discrete differential geometry. The algorithm tests to verify the developed algorithm with sample plates of a real ship data have been performed.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.993-996
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• 2008

Compression stress block used to concrete structure design substitutes equivalent triangle, rectangle, trapezoid and parabola-rectangle stress block for actual concrete stress distribution. Its shape is different in design code of the major advanced countries. It reflects the material feature of each of country. Presently, compression stress block of korea concrete design code is equal to it of ACI code that doesn't reflect the material feature of the high strength concrete. So, many research conclusions showed that it is not reasonable. The study compares concrete stress blocks of the major advanced countries and does an experiment on concrete compression stress block to know the material feature of the concrete in korea. It obtains the operating load and the concrete strain in experiment and draw stress block parameters. It compares stress block parameters applied to design code with those by the experiment conclusion. In addition, It compares and analyses nominal axial force-moment diagram by the stress block of the major advanced countries.

• Journal of the Korean Institute of Intelligent Systems
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• 제23권1호
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• pp.57-64
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• 2013

In this paper, we propose the classification method of medicine bottle images using the features with color and size information. It is difficult to classify with size feature only, because there are many similar sizes of bottles. Therefore, we suggest a classification method based on color information, which robust to illumination variations. First, we extract MBR(Minimum Boundary Rectangle) of medicine bottle area using Binary Threshold of Red, Green, and Blue in image and classify images with size. Then, hue information and RGB color average rate are used to classify image, which features are robust to lighting variations. Finally, using SURF(Speed Up Robust Features) algorithm, corresponding image can be found from candidates with previous extracted features. The proposed method makes to reduce execution time and minimize the error rate and is confirmed to be reliable and efficient from experiment.