• Title/Summary/Keyword: Comparison Research

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International Time Comparison by TWSTFT and GPS at KRISS

  • Hwang, Sang-wook;Lee, Chang Bok;Lee, Jong Koo;Lee, Young Kyu;Lee, Sang Jeong;Yang, Sung-hoon
    • Journal of Positioning, Navigation, and Timing
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    • v.5 no.2
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    • pp.67-74
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    • 2016
  • In this paper, time comparison is performed with standardization institution in Japan using a Two-Way Satellite Time and Frequency Transfer (TWSTFT) technique as one of the methods for high precision time comparison. To analyze the performance of time comparison in the TWSTFT method, time comparison results via the Global Positioning System (GPS) code and carrier wave are analyzed. Through the time comparison performance, frequency stability is analyzed using modified Allan deviation and by this result, characteristics of time comparison of the TWSTFT that is utilized in international time comparison are presented.

A Logical Framework of Comparison Shopping Effectiveness and Comparison Challenge Methodology

  • Lee, Jae-Won
    • Proceedings of the CALSEC Conference
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    • 2005.03a
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    • pp.130-134
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    • 2005
  • This research describes the comparison broker's role and its effectiveness measurement using a developed logical framework of comparison shopping service. And verifies that seller-led comparison challenge method provide comparison information of products to buyers more efficiently. In electronic commerce, buyer's satisfaction of purchase (S) can be defined as an interactive function between seller's competitiveness vector (P) of products that supplied to the market, and buyer's informed level vector (B) of products that is known from a lot of sources. Then the buyer's informed level can be changed through the information analysis among products by transformation process using comparison matrix (C). So the role of comparison shopping is to construct a comparison matrix and to serve it to the buyers, and to change the buyer's informed level. The changed informed level influences a buyer's satisfaction, that improved satisfaction of purchase is defined as the effectiveness of comparison shopping. As a perfect provision and usage of comparison matrix is impossible cause of cognitive limit, the most efficient method for improving the comparison effectiveness is the comparison challenge that detects the comparison elements of the largest buyer's information efficiency, and then to be compared between elementary products selectively. This research verifies the substantial superiority of comparison challenge through television market data experiments.

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International Comparison of high resistance and Mutual Recognition between National Metrology Institutes (전기저항의 국제비교 및 계측기술에 관한 국제적 상호인정 추세)

  • Yu, Kwang-Min;Ryu, Je-Cheon;Kang, Jeon-Hong;Kim, Han-Jun
    • Proceedings of the KIEE Conference
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    • 1999.07b
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    • pp.606-608
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    • 1999
  • Mutual Recognition Agreement(MRA) between national metrology institutes is started on October 1999 and International Key Comparison is essentially to be used as technical basis for the agreement. High resistance is one of the Key Comparison and high resistance measurement system is established in KRISS for the purpose of the Key Comparison. Total combined uncertainty of the system is about 4ppm in $10M{\Omega}$ and 8ppm in $1G{\Omega}$. With the system, the difference of comparison results for $10M{\Omega}$ and $1G{\Omega}$ among KRISS, VNIIM in Russia and NIM in China is agreed about 6ppm within total combined uncertainty of three institutes.

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Inter-comparison Test of Lightning Impulse High Voltage Reference Measuring System (뇌충격 고전압 기준측정시스템의 국제비교시험)

  • Kim, Min-Kyu;Lee, Jeong-Gi;Choi, Ik-Soon;Jeong, Ju-Young;Kim, Ik-Soo
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.2217-2219
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    • 2005
  • In this paper, an inter-comparison test of lightning impulse reference measurement system between Korea and Japan is reported. At present, such a direct comparison test as the activity to sustain the traceability of the measurement system is generally proposed. Due to the inter-comparison test, ascertaining the grade of the measurement uncertainty and maintaining the level of reference system are accomplished.

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Analysis and Prototype Design for Price Comparison in China and Korea

  • Park Jong-Hoon;Kim Chul-Won
    • Journal of information and communication convergence engineering
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    • v.3 no.3
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    • pp.152-156
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    • 2005
  • Korea-China with the fastest speed Internet Broad Band, has achieved many progresses on Internet shopping. Especially, Korea has made a great effort on comparison website construction. A research prototype design and exploratory analysis are presented to assess success factors and impacts of Korea and China price comparison websites. For different user groups, the relationships between the characteristics of technology and tasks, usage, and organizational impacts were analysed. It shows us how to improve the applicability of fit-viability of the price comparison web sites in China after analysis. These results indicate a need for simple but highly functional price comparison applications. And we designed a sample model to include an interactive web service system for price comparison sites that complement existing information systems. This paper provides a basis for further research aiming to improve the design and management of business applications based on emerging technologies of web service and browser for information management.

Deriving Weights in The Multiattribute Decision Making with Imprecise Pairwise Comparison (부정확한 쌍대비교정보를 갖는 댜요소의사결정문제에서의 가중치 산출)

  • 정병호;조권익
    • Journal of the Korean Operations Research and Management Science Society
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    • v.19 no.2
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    • pp.75-84
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    • 1994
  • The uncertainty in the relative weights of a pairwise comparison matrix n Multi-attribute Decision Making (MADM) is caused by imprecise preference information of decision maker. In this paper, it is shown how weight of attributes can be derived from the pairwise comparison matrix with interval pairwise comparison. The preference information of each pair of attributes with a point pairwise comparison is combined with an interval pairwise comparison in order to estimate a point pairwise comparison for a pair of attributes with the imprecise preference information. A numerical example shows the suggested procedure for deriving weights of attributes.

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Comparison of Antenna Parameters of R-/S-Band Standard Gain Horn Antennas

  • Kang, Jin-Seob;Kim, Jeong-Hwan;Park, Jeong-Il
    • Journal of electromagnetic engineering and science
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    • v.15 no.4
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    • pp.224-231
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    • 2015
  • A comparison of the antenna parameters for R-band (1.7-2.6 GHz) and S-band (2.6-3.95 GHz) standard gain horn antennas has been performed by the Korea Research Institute of Standards and Science (KRISS), together with seven domestic participants from private companies and public institutions. Its purpose, as a proficiency test program of the 'Antenna Measurement Club' of KRISS, was to check equivalences in antenna parameter measurements between KRISS and the participants, particularly in the R-/S-band, to support antenna manufacturers and end users in Korea. The measurement parameters of this comparison are the power gain, radiation pattern, and reflection coefficient of the traveling standards for R-/S-band pyramidal standard gain horn antennas. The comparison used a gain comparison method and an extrapolation method to measure the power gain of the two traveling standards; the radiation patterns were measured in the far-field region of the transmitting and receiving antennas.

Measurement of triple point of water temperature for improvement of the national standards and key comparison (국가표준향상과 핵심국제비교를 위한 물의 삼중점 온도 측정)

  • Yang, Inseok;Lee, Young Hee
    • Journal of Sensor Science and Technology
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    • v.30 no.5
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    • pp.349-356
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    • 2021
  • The Korea Research Institute of Standards and Science (KRISS), a National Metrology Institute of Korea, participated in the second-round of the international key comparison CCT-K7.2021 of triple point of water (TPW) cells. For the key comparison, three TPW cells, one of which had been used in the old CCT-K7 comparison, were assigned as the national standard of the TPW. The temperature difference (ΔT) between the average of the new and old national standards and ΔT between the new national standard and the transfer standard were measured. The comparison between the new and old national standards indicated a temperature increase of 69.5 µK after both the standards were corrected for the isotopic composition. The uncertainty of the national standard of the TPW temperature was 28 µK, and the uncertainty of ΔT was 14 µK. Three aspects of improvements in the new comparison compared to the old one were noted: (1) inclusion of two quartz cells in the national standard strengthens its long-term stability; (2) the standard deviation associated with the measurement of ΔT was reduced from 21 µK to 9.6 µK; (3) and the measured immersion profile of the TPW cells was much closer to the theoretically predicted dependence.

A Study on Comparison Test for Brake Disc Lining (제동디스크라이닝의 비교시험 연구)

  • Chung Jong-Duk;Kwon Sung-Tae;Han Seok-Yoon;Park Ki-Joon;Chun Hong-Jung
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.43-48
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    • 2005
  • In order to facilitate technical exchange among nations and/or institutes through the establishment of mutual recognition and the reliability guarantee of testing results by testing standards standardization, the interlaboratory comparison tests on brake discs and linings between KRRI and CARS were conducted. So far, two ways of comparison tests were performed for a better understanding of mutual recognition and standardization in railroad brake linings between Korea and China. In this paper, the first and second comparison testing results have been summarized, and the suggestions for the future research work are also presented to encourage extensive research on comparison study of railroad brake discs and linings between KRRI and CARS. Eventually, the final goal of the current research will be the establishment of standardization of railroad testing standards.

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Comparison Shopping Effectiveness Model and its Strategic Usage in e-Commerce (전자상거래 비교구매 효과성 모형과 활용 전략)

  • Lee, Jae-Won
    • The Journal of the Korea Contents Association
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    • v.11 no.5
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    • pp.291-301
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    • 2011
  • This research describes the comparison broker's role and its effectiveness measurement framework of comparison shopping. We verified seller-led comparison challenge method provide comparison information of products to buyers more efficiently. Buyer's satisfaction of purchase (S) can be defined as an interactive function between seller's competitiveness vector (P) of products that supplied to the market, and buyer's informed level vector (B) of products that is known from a lot of sources. Then the buyer's informed level can be changed through the information analysis among products by transformation process using comparison matrix (C). So the role of comparison shopping is to construct a comparison matrix and to serve it to the buyers, and to change the buyer's informed level. The changed informed level influences a buyer's satisfaction, that improved satisfaction of purchase is defined as the effectiveness of comparison shopping. As a perfect construction and usage of comparison matrix is impossible, a more efficient method for improving the comparison effectiveness is the comparison challenge. This research shows that comparison shopping makes 9.32% and comparison challenge makes 19.11% enhancement of comparison effectiveness through television market data experiments.