• Journal of the Korean Data and Information Science Society
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• v.24 no.1
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• pp.161-170
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• 2013

The FX (Foreign Exchange) is a form of exchange for the global decentralized trading of international currencies. The simple sense of Forex is simultaneous purchase and sale of the currency or the exchange of one country's currency for other countries'. We can find the consistent rules of trading by comparing the gradient boosting method and the decision trees methods. Methods such as time series analysis used for the prediction of financial markets have advantage of the long-term forecasting model. On the other hand, it is difficult to reflect the rapidly changing price fluctuations in the short term. Therefore, in this study, gradient boosting method and decision tree method are applied to analyze the short-term data in order to make the rules for the revenue structure of the FX market and evaluated the stability and the prediction of the model.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.469-472
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• 2008

In this paper, we discuss the recent trends on the passive UHF RFID tag chip design techniques and several important system parameters. We also summarize link budget studies on both conventional and modem UHF RFID communications. The paper highlights the reverse link limited case, which has known to be the minor concern if reader continuous wave (CW) can reach the tag in sufficient level. This makes sense when the tag sensitivity is rather high (over 10-12${\mu}W$); however, since the tag chip fabrication technologies have been developed by time, the tag chip threshold levels are now less-dominant in determining link margin. If the tag limitation can be alleviated, the forward link limited case can be resolved; thus, we rather focus on the path-loss problem. Since the path-losses are still exist in both forward and reverse links, and it can be doubled while CW travels the reader-tag-reader path because forward link and reverse link are on the same distance. Consider if reader receiver sensitivity is very high in the worst case. In this case, weaken tag response (i.e., backscatters) cannot reach the level that reader receiver can process tag data; bit-error rate can be higher. Overall, backscatter levels should be high enough so that reader receiver can correctly function. After discussing link budget, we carried out practical measurements on fading effects between two circularly polarized UHF RFID antennas in a small scale area.

• Journal of Korea Multimedia Society
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• v.14 no.4
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• pp.538-545
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• 2011

Today, there is a wide variety of digital contents on the Internet. Especially, comic images are one of popular digital contents. Most of them are scanned from comic books by digital scanners, but they were not normalized in sense of their size, skew and boundary margin. The normalization is very important step in comic image analysis. It can be achieved by finding out-boundary rectangles in comic images. In this paper, we propose a method for detecting the out-boundary rectangle using the gradient Radon transform in comic images. We applied the Radon transform using image gradients to extract line segments which are the out-boundary rectangle sides' candidates in comic images. The final out-boundary rectangle can be detected by local histogram and the candidate line segments. Experimental results show that our proposed method effectively detect the out-boundary rectangle in comic images.

• Environmental and Resource Economics Review
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• v.12 no.4
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• pp.637-661
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• 2003

This paper analyzes the impact of import liberalization of petroleum product market in 1997 on the behavior of a domestic industry, regarded as a typical oligopoly. Based on the theory of implicit cartel, two regression equations were formulated and estimated for domestic production and refinery margin using monthly data for the period from Jan. 1994 to June 2003. Estimation results show that not only did domestic production rise sharply but also the refining cost fell substantially throughout 1996 before the actual liberalization of imports, Such a response is clearly consistent with the implicit cartel theory, which suggests that once the difficulty of maintaining a cartel in the future is recognized, the cartel immediately collapses and anticipation of import liberalization can cause immediately lowering market price as well as an immediate expansion of the supply by a domestic industry. However, the significant reduction of refinery cost accompanied by a large contraction in domestic output after the actual implementation of import liberalization can be explained by the collapse of implicit cartel caused by the anticipated liberalization of imports. Thus, import liberalization in the sense of allowing entry of foreign producers into domestic market has seemed to be an effective means to weaken market power and induce more competitive conduct of domestic firms.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.2
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• pp.123-130
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• 2016

With the development of fast construction mode in shipbuilding market, the demand on accuracy management of hull is becoming higher and higher in shipbuilding industry. In order to enhance production efficiency and reduce manufacturing cycle time in shipbuilding industry, it is important for shipyards to have the accuracy of ship components evaluated efficiently during the whole manufacturing cycle time. In accurate shipbuilding process, block accuracy is the key part, which has significant meaning in shortening the period of shipbuilding process, decreasing cost and improving the quality of ship. The key of block accuracy control is to create a integrate block accuracy controlling system, which makes great sense in implementing comprehensive accuracy controlling, increasing block accuracy, standardization of proceeding of accuracy controlling, realizing "zero-defect transferring" and advancing non-allowance shipbuilding. Generally, managers of accuracy control measure the vital points at section surface of block by using the heavy total station, which is inconvenient and time-consuming for measurement of vital points. In this paper, a new measurement method based on point clouds technique has been proposed. This method is to measure the 3D coordinates values of vital points at section surface of block by using 3D scanner, and then compare the measured point with design point based on ICP algorithm which has an allowable error check process that makes sure that whether or not the error between design point and measured point is within the margin of error.

• Journal of Gastric Cancer
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• v.4 no.3
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• pp.143-148
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• 2004

Purpose: To determine the clinical value of the Siewert classification for gastic-cancer patients in Korea, we evaluated and compared the clinicopathologic factors of type II and type III cancer. Materials and Methods: The medical records of 89 consecutive patients who had undergone surgery for an adenocarcinoma of the gastroesophageal junction (GEJ) at the Department of Surgery, Hanyang University Hospital, between Jun. 1992 and Dec. 2003 were reviewed retrospectively. Results: There were one patient with type I, 12 pateints with type II and 77 patients with type III. During the same period, 1,341 patients underwent surgery for a gastric carcinoma, so proportion of GEJ cancer being $6.6\%$. The median followup duration was 31 months (range: $2\∼135$ months), and the follow-up rate was $100\%$. Between type II and type III cancers, there were no significant differences in the clinicopathologic variables including age, sex, gross appearance, histologic type, depth of invasion, and pathologic stage. The longest diameter of the tumor was larger in type III ($6.1\pm2.1$ cm) than in type II ($3.9\pm1.1$ cm)(P=0.001). A total gastrectomy with Roux-en-Y esophagojejunostomy was done most frequently, while jejunal interposition was done in 3 cases of type II and 2 cases of type III. More than a D2 lymphadenectomy was done all cases. The numbers of dissected lymph nodes and metastatic lymph nodes in type II were 43.8 and 5.8 respectively, while they were 49.8 and 8.1 in type III, but the difference between the two groups were not statistically significant. The mean length of the proximal resection margin was $15\pm5$ mm in type II and $21\pm13$ mm in type III, but this difference was not statistically significanct. The time to recurrence after operation was 19.3 months in type II and 16.9 months in type III. The five-year survival rates of type II and III were $68.8\%\;and\;52.7\%$ respectively, but difference was not significant. Conclusion: There were no significant differences in the clinicopathologic variables, including survival rate, between type II and type III cancers in Korean patients According to these findings, it appears to be reasonable to classify type III cancer as a cardia cancer in a broad sense.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.10
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• pp.7-14
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• 2008

In this paper, we designed the HVIC(High Voltage Gate Driver IC) which has improved noise immunity characteristics and high driving capability. Operating frequency and input voltage range of the designed HVIC is up to 500kHz and 650V, respectively. Noise protection and schmitt trigger circuit is included in the high-side level shifter of designed IC which has very high dv/dt noise immunity characteristic(up to 50V/ns). And also, rower dissipation of high-side level shifter with designed short-pulse generation circuit decreased more that 40% compare with conventional circuit. In addition, designed HVIC includes protection and UVLO circuit to prevent cross-conduction of power switch and sense power supply voltage of driving section, respectively. Protection and UVLO circuit can improve the stability of the designed HVIC. Spectre and Pspice circuit simulator were used to verify the operating characteristics of the designed HVIC.

• Journal of Fashion Business
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• v.6 no.1
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• pp.43-52
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• 2002

The purpose of this study was to present the plan for activation and rationalization of production of ladies' jacket and provide basic materials for improvement of the development of technologies in relation to the productivity improvement of ladies' jacket and the achievement of high quality product. For this purpose, this study attempted to investigate the present situation of jacket manufacturing process. The data is related with local ladies' jacket manufacturing companies in Seoul snd Kyonggi area. The results of this study are as follows. 1. 87.8% of the business firms responded that they acquired the productive process of jacket based on their own knowhow and 80.5% was aware of the need for the analysis of each process. The highest proportion of the business firms(65.9%) pointed out that the advantage of process analysis was the alleviation of the production time. 2. The jacket manufacturing process was made up of 4 stages such as the process of frontal/rear plate $\rightarrow$ the process of accessories $\rightarrow$ the process of completion $\rightarrow$ the process of finishing in a broad sense but composed of a total of 19 stages in detail. 3. Attachment of the sleeves(73.2), attachment of the collar(41.5%) and the formation of the overall silhouette(22.0%) were raised as the challenge in manufacturing ladies' jacket. 4. Most of the sewing business firms made use of the method of completing the collar and then stitching the outer material and the inner collar, and the line of the bodice and the outer collar as the method of stitching the tailored collar. and many of them used the method of completing the collar and then inserting it between the line of the bodice and the outer material and stitching it as the method of stitching the stand collar. They had a preference for the method of completing the sleeve and connecting it to the bodice as the method of stitching the sleeve. and used the method of treating the margin to seam of semi-lined and unlined jacket by treating it with the bias tape.