• 한국정밀공학회지
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• 제26권6호
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• pp.68-73
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• 2009

One of the traditional optical methods to monitor a tool is a CCD sensor-based vision system which captures an aspect of the tool in real time. In the case using the CCD sensor, specific lens-modules are necessary to monitor the tool with higher resolution than its pixel size, and a microprocessor is required to attain desired data from captured images. Thus theses additional devices make the entire measurement system complex. Another method is to use a pair of an optical source and a detector per measuring axis. Since the method is based on the intensity modulation, the structure of the measurement system is simper than the CCD sensor-based vision system. However, in the case measuring the three dimensional position of the tool, it is difficult to apply to micro machine-tools because there may not be space to integrate three pairs of an optical source and a detector. In this paper, in order to develop a tool-origin measurement system which is employed in micro machine-tools, the improved method to measure a tool origin in x, y and z axes is introduced. The method is based on the intensity modulation and employs one pair of an optical source radiating divergent beams and a quadrant photodiode to detect a three dimensional position of the tool. This paper presents the measurement models of the proposed tool-origin sensor. The models were verified experimentally The verification results show that the proposed method is possible and the induced models are available for design.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.148-153
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• 1998

In order to control thermal deformation of machine origin of machine tools due to internal and external heat sources, the real-time compensation system has been developed. First, GMDH models were constructed to estimate thermal deformation of machine origin for a vertical machining center through the measurement of deformation data and temperature data of specific points on the machine tool. Thermocouples and gap sensors are used respectively for measurement. These models are nonlinear equations with high-order polynomials and implemented in a multilayered perceptron type network structure. Secondly, work origin shift method were developed by implementing digital I/O interface board between CNC controller and IBM-PC. The work origin shift method is to shift the work origin by the compensation amounts which is calculated by pre-established GMDH model. From the experimental result, thermal deformation of machine origin was reduced to below $\pm$5${\mu}{\textrm}{m}$.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.213-218
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• 1997

Thermal deformation of machine origin of machine tools due to internal and external heat sources has been the most important problem to fabricate products with higher accuracy and performance. In order to solve this problem, GMDH models were constructed to estimate thermal deformation of machine origin for a vertical machining ceneter through measurement of temperature data of specific points on the machine tool. These models are nonlinear equations with high-order polynomials and implemented in a multilayered perceptron type network structure. Input variables and orders are automatically selected by correlation and optimization procedure. Sensors with small influence are deleted automatically in this algorithm. It was shown that the points of temperature measurement can be reduced without sacrificing the estimation accuracy of $\pm$5${\mu}{\textrm}{m}$. From the experimental result, it was confirmed that GMDH methodology was superior to least square models to estimate the thermal behavior of machine tools.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.405-406
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• 2010

• 한국공작기계학회논문집
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• 제13권3호
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• pp.16-23
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• 2004

Thermally induced errors of machine tools have been recognized as one of the most important issues in precision machining. This is probably the most formidable obstacle to obtain high level of machining accuracy. To this regard, the experimental compensation methodologies such as software-based method or origin shift of machine tool axes have been suggested. In this research, to cope with thermal deformation, a model based correction was carried out with the function of an external machine coordinate shift. Models with multi-linear regression or neural network were investigated to selected a good one for thermal compensation. Consequently, multi-linear regression model combined with origin shift was verified good enough form the machining of dot matrices of plate with ball end milling.

• 무역학회지
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• 제45권5호
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• pp.223-238
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• 2020

In the environment of protectionism and bilateral trade agreements, Korea has promoted the conclusion of FTAs for its export-oriented trading policy, and 16 FTAs have entered into force at present. The main goal of this paper is to introduce the ISI system and its benefits and to extend the preferential rule of origin regime by using the Integrated Sourcing Initiative in the U.S. Code of Federal Regulations. The ISI illustrates with impressive clarity the fact that it considered as a tool of expanding the geographic limit of states and maximizing the global sourcing strategy of multinational corporations, allowing the developing countries to gain access to the market of developed ones that avoid the complexity and costs of many rules of origin regimes. This paper utilizes the literature research and analyzes a case study of FTAs which have adopted the ISI system. In conclusion, it presents several implications of additional measures to satisfy rules of origin in Korea's existing FTAs relating to the global supply chain strategy.

• Journal of Information Technology Applications and Management
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• 제20권1호
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• pp.87-106
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• 2013

This study is to explore the airline network patterns of Incheon and Narita International Airports using passenger flight departure and arrival data of the two airports. The so-called Origin-Destination data is collected from the airports' websites and some of the important data items are flight number, city of origin, destination city, departure/arrival time, number of flights, and delay time. A snowflake schema dimensional model is proposed and implemented. Tableau Public, a well-known visual analytic tool, is used to connect the dimensional model and played an important role in navigating the data space to find interesting and visual patterns among corresponding airports and airlines. For the efficiency of analyzing this spacious data mart, data visualization method was used. Four types of visualization method proposed by Yau was used; visualizing patterns over time, visualizing proportions, visualizing relationships, and visualizing spatial relationships. The strength of connectivity of each flight segments is calculated to evaluate the degree of globalization of Seoul and Tokyo. We anticipate that various patterns and new findings produced by the data mart would provide airline managers, airport authorities, and policy makers in the field of travel and transportation with insightful information.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1151-1151
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• 2001

The international coffee trade is conducted almost exclusively with green coffee. The main coffee producing countries include Brazil, Columbia, Indonesia, Mexico and the Ivory Coast. About 99 % of the coffee grown throughout the world belong to two coffee plant varieties that are commonly known as Arabica and Robusta. The quality of green coffee can be assessed according to several ISO standards (1,2,3,4,5). However, no official international standards for the authenticity of green coffee have been issued. It is important to know the country of origin of the coffee for the purposes of fair international trade. The geographic origin of the coffee is often stated on the label of coffee products such as speciality roasted and soluble coffees. Near Infrared Spectroscopy (NIR) is an accepted technique for quantitative analysis of various parameters in routine QC analysis of food products. It would appear to be a promising candidate as a tool for identification of green coffee origin and numerous feasibility studies have appeared in the literature on its use for soluble, roasted and green coffee variety identification as well as identification of arabica or robusta coffees. NIR spectrophotometers when configured in the reflectance mode are able to perform a complete profile of the NIR spectrum on whole beans. The data can then be interpreted by discriminant chemometrics data analysis. This is the approach used in the present study.

• 한국정밀공학회지
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• 제31권4호
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• pp.297-301
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• 2014

The biggest factors, which lower the machining accuracy of machine, are thermal deformation and chatter vibration. In this article, we introduce the development case of a device and technology that can automatically compensate thermal deformation errors of machine during long-time processing on the machine tool's CNC (Computerized Numerical Controller) in real time. In machine processing, the data acquisition of temperature signal in real time and auto-compensation of the machine origin of machine tools depending on thermal deformation have significant influence on improving the machining accuracy and the rate of operation. Thus, we attempts to introduce the related contents of the development we have made in this article : The development of a device that embedded the acquisition part of temperature data, linear regression to get compensation value, compensation model of neural network and a system that compensates the machine origin of machine tool automatically during manufacturing process on the CNC.

• 한국컴퓨터그래픽스학회논문지
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• 제30권3호
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• pp.9-22
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• 2024

이동 정보에 대한 분석은 다양한 사회문제 해결에 도움이 될 수 있으며, 이러한 이동 정보를 정량화하여 나타낸 대표적인 데이터 중 하나가 Origin-Destination(OD) 데이터이다. 기존 연구들에서는 OD 데이터에 시각화 방법론을 도입했으나, 이러한 시각화 도구를 실제 사회 문제 해결에 사용하여 사용성을 평가한 적은 없다. 본 연구에서는 사회 문제해결에 용이한 시각화 도구(이하 SeoulOD-Vis)를 3가지 모듈(지도 시각화, 조건 선택, 세부 정보 표기)에 기반해 개발하였다. 그리고 28명의 피험자를 대상으로 SeoulOD-Vis와 동일한 OD 데이터를 기반으로 제작된 공개된 시각화 도구(기존 시각화 도구)의 사용성을 비교하였다. 그 결과, SeoulOD-Vis 가 기존 시각화 도구보다 높은 사용성 및 문제 수행 성능을 보였으며, 이는 SeoulOD-Vis에 포함된 '조건 선택' 및 '세부 정보 표기' 모듈에 기인했다. 또한, '지도 시각화' 모듈에서 제공하는 히트맵 및 플로우맵은 각기 다른 목적으로 사용되며 다양한 사회 문제 해결에 도움을 줄 수 있음을 확인했다. 본 연구의 결과는 추후 이동 정보를 활용한 사회 문제 해결을 위한 시각화 도구 개발 및 이를 통한 다양한 사회 문제 해결에 기여할 수 있을 것으로 기대된다.