• Journal of the Korean Institute of Telematics and Electronics
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• v.18 no.5
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• pp.1-9
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• 1981

Experimental results on a 4-bit charge-coupled A/D converter are described. Major operations in the successive approximation algorithm are implemented in a monolithic chip, CCADC, which was fabricated usir p-channel CCD technology, with its die size of 4,200 mil2 Typical operating frequency range has been found out to be from 500Hz to 200kHz. In that frequency range, no missing code has been found in the whole signal range of 2.4 volts for ramp signal slewing at 1 LSB/(sampling time). A discussion is made on several layout techniques to conserve the nominal binary ratio of (8:4:2:1) among the areas of four adjacent potential wells (M wells), whose charge storing capacities correspond to each bit magnitude - 3.6 pC, 1.8 pC, 0.9 pC, and 0.45 pC nominal in the order of MSB to the LSB. The effect of 'dump slot', which is responsible for the excessive nonlinearity (2$\frac{1}{2}$LSB) in the A/D converter, is explained. A novel input scheme called 'slot zero insertion' to circumvent the deleterious effects of the dump slot is described with the experimental results.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.6
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• pp.137-146
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• 1998

Recently many devices print electronic images in a variety of ways. The reproduced color, however, is different from the original color because of the difference of hardware characteristics. To maintain device independent color, gamut mapping method is proposed. The proposed color gamut mapping uses nonlinear intensity mapping and clipping for saturation mapping on HSI color space. In the dithering operation, expanded nonlinear ordered dithering and modified error diffusion are proposed. The proposed ordered dithering uses expanded nonlinear quantization which considers overlapping phenomena of neighbored printing dots. In the modified error diffusion, quantization errors to be diffused are adjusted to improve both image blur and color change produced in the error diffusion. So, the printed image is similar to the image of monitor. Our results indicate that proposed algorithm can produce high quality image in the low bit color devices.

• School Mathematics
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• v.7 no.2
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• pp.123-137
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• 2005

Elementary combinatorial problem may be classified into three different combinatorial models(selection, distribution, partition). The main goal of this research is to determine the effect of type of combinatorial operation and implicit combinatorial model on problem difficulty. We also classified errors in the understanding combinatorial problem into error of order, repetition, permutation with repetition, confusing the type of object and cell, partition. The analysis of variance of answers from 339 students showed the influence of the implicit combinatorial model and types of combinatorial operations. As a result of clinical interviews, we particularly noticed that some students were not able to transfer the definition of combinatorial operation when changing the problem to a different combinatorial model. Moreover, we have analysed textbooks, and we have found that the exercises in these textbooks don't have various types of problems. Therefore when organizing the teaching , it is necessary to pose various types of problems and to emphasize the transition of combinatorial problem into the different models.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.9
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• pp.89-95
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• 2015

In this paper, we propose a real-time two-dimensional bar code detection system even at long range using a vision technique. We first perform short-range detection, and then long-range detection if the short-range detection is not successful. First, edge map generation, image binarization, and connect component labeling (CCL) are performed in order to select a region of interest (ROI). After interpolating the selected ROI using bilinear interpolation, a location symbol pattern is detected as the same as for short-range detection. Finally, the symbol pattern is arranged by applying inverse perspective transformation to localize bar codes. Experimental results demonstrate that the proposed system successfully detects bar codes at two or three times longer distance than existing ones even at indoor environment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.10
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• pp.1305-1313
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• 2013

In this study, a method to apply feature-based simplification to boundary representation models is proposed. For feature-based simplification, a volume decomposition tree is created from a boundary representation model. The volume decomposition tree is represented by regularized Boolean operations of additive volumes, subtractive volumes, and fillet/round/chamfer volumes, and it is generated by stepwise volume decomposition, which consists of fillet/round/chamfer decomposition, wrap-around decomposition, volume split decomposition, and cell-based decomposition. After the volume decomposition tree is transformed to an infix expression, the CAD model can be simplified by reordering the volumes. To verify the proposed method, a prototype system was implemented, and experiments on test cases were conducted. From the results of the experiments, it is verified that the proposed method is useful for simplifying CAD models based on boundary representation.

• Journal of Korea Spatial Information System Society
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• v.7 no.3 s.15
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• pp.55-65
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• 2005

This paper presents a bulk insertion technique for efficiently inserting data items. Traditional moving object database focused on efficient query processing that happens mainly after index building. Traditional index structures rarely considered disk I/O overhead for index rebuilding by inserting data items. This paper, to solve this problem, describes a new bulk insertion technique which efficiently induces the current positions of moving objects and reduces update cost greatly. This technique uses buffering technique for bulk insertion in spatial index structures such as R-tree. To analyze split or merge node, we add a secondary index for information management on leaf node of primary index. And operations are classified to reduce unnecessary insertion and deletion. This technique decides processing order of moving objects, which minimize split and merge cost as a result of update operations. Experimental results show that this technique reduces insertion cost as compared with existing insertion techniques.

• Journal of Internet Computing and Services
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• v.3 no.2
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• pp.79-85
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• 2002

In open communication architecture, application systems consist of objects distributed in lots of computing nodes. To reduce complexity of development. and management of distributed software, to manage efficiently distributed objects and to provide realtime service, the mechanisms for object group management and communication are needed in distributed environment. In this paper we compose object groups and provide reliable group communication mechanism based on CORBA which can adopt a new service without lots of changes on existing system. Group consist of some subgroups that subgroup manager manages for improving the efficiency of group management and message ordering is kept by using sequencer, Communication method among groups uses multicast based on paint to point communication as well as IP multicast and we provide high performance by using selective retransmission of message through message history, We analyze the performance of the proposed mechanism through simulation in distributed environment.

• The Journal of the Korea Contents Association
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• v.11 no.5
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• pp.125-137
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• 2011

Recently the research on the system using images taken from camera phones as input is actively conducted. This paper proposed a system that shows wine pictures which are similar to the input wine label in order. For the calculation of the similarity of images, the representative color of each cell of the image, the recognized text color, background color and distribution of feature points are used as the features. In order to calculate the difference of the colors, RGB is converted into CIE-Lab and the feature points are extracted by using Harris Corner Detection Algorithm. The weights of representative color of each cell of image, text color and background color are applied. The image similarity is calculated by normalizing the difference of color similarity and distribution of feature points. After calculating the similarity between the input image and the images in the database, the images in Database are shown in the descent order of the similarity so that the effort of users to search for similar wine labels again from the searched result is reduced.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.4
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• pp.74-88
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• 2007

In order to automate the process of mail sorting by delivery sequence, it is necessary to prepare a postal address database and to interpret written addresses on the mail-pieces with the database and OCR technology. The address database is a critical factor of automation and informatization of postal service since it could be used not only in address recognition but also in various mail processing. In this study, we design the schema of postal address database, design the postal address file based on it and explain the method of address interpretation and retrieval using it. We analyze infonnation requirements for transformation of postal address into the standardized format and consider them in the process of design. The postal address file can be used by address matching or retrieval system as well as by Hangul address recognition system for automation of delivery sequence mail-sorting.

• Journal of Conservation Science
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• v.32 no.4
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• pp.449-457
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• 2016

A stoneware bottle was recovered from the Incheon Yeongheungdo Shipwreck in 2013. Primary observations showed that this object had a sealed opening and was covered with a foreign material. After it was cleaned via mechanical and chemical methods, wave patterns were observed on the outer surface of the bottle and a yellowish-brown transparent material was found within. In this paper, the process of conserving the stoneware bottle and the analysis conducted on the unknown material found within is explained. The conservation process included steps such as cleaning, desalination and restoration. After of the missing area located at the rim, the original shape of the bottle was made clear. In addition, the unknown inner material was analyzed using FT-IR and GC-MS. Results showed that the material is similar to golden lacquer. It is speculated that the Yeongheungdo Ship had wrecked during the Unified Silla period while carrying a bottle loaded with golden lacquer.