• Title/Summary/Keyword: service reference model

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Parametric Analysis of the Solar Radiation Pressure Model for Precision GPS Orbit Determination

  • Bae, Tae-Suk
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.35 no.1
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    • pp.55-62
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    • 2017
  • The SRP (Solar Radiation Pressure) model has always been an issue in the dynamic GPS (Global Positioning System) orbit determination. The widely used CODE (Center for Orbit Determination in Europe) model and its variants have nine parameters to estimate the solar radiation pressure from the Sun and to absorb the remaining forces. However, these parameters show a very high correlation with each other and, therefore, only several of them are estimated at most of the IGS (International GNSS Service) analysis centers. In this study, we attempted to numerically verify the correlation between the parameters. For this purpose, a bi-directional, multi-step numerical integrator was developed. The correlation between the SRP parameters was analyzed in terms of post-fit residuals of the orbit. The integrated orbit was fitted to the IGS final orbit as external observations. On top of the parametric analysis of the SRP parameters, we also verified the capabilities of orbit prediction at later time epochs. As a secondary criterion for orbit quality, the positional discontinuity of the daily arcs was also analyzed. The resulting post-fit RMSE (Root-Mean-Squared Error) shows a level of 4.8 mm on average and there is no significant difference between block types. Since the once-per-revolution parameters in the Y-axis are highly correlated with those in the B-axis, the periodic terms in the D- and Y-axis are constrained to zero in order to resolve the correlations. The 6-hr predicted orbit based on the previous day yields about 3 cm or less compared to the IGS final orbit for a week, and reaches up to 6 cm for 24 hours (except for one day). The mean positional discontinuity at the boundary of two 1-day arcs is on the level of 1.4 cm for all non-eclipsing satellites. The developed orbit integrator shows a high performance in statistics of RMSE and positional discontinuity, as well as the separations of the dynamic parameters. In further research, additional verification of the reference frame for the estimated orbit using SLR is necessary to confirm the consistency of the orbit frames.

A Study on a Model Collection Development Policy for Children and Young Adults Libraries - with a special reference to the National Library for Children and Young Adults, Korea - (어린이청소년도서관 장서개발정책 모형 연구 - 국립어린이청소년도서관을 중심으로 -)

  • Chang, Durk-Hyun;Lee, Yeon-Ok;Yoon, Hee-Yoon
    • Journal of Korean Library and Information Science Society
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    • v.45 no.2
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    • pp.179-203
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    • 2014
  • The main objective of this study is to set a Collection Development Policy(CDP) for the National Library for Children and Young Adults(NLCY). Every library, in order to accomplish its duty, should maintain a written collection development policy. This paper, in this regard, strives to propose a model to comprise of basic principles of collection development of NLCY for the effective management of resources by the types and subjects. Major emphasis was put on the nature of the library as a repository and a service point for children and young adults, and a hub for children-related research. As a result, a model collection development policy appropriate for NLCY has been proposed by analyzing cases in other countries to guide establishing principles for determining and analyzing the types and magnitude of the collection acquisition.

An Empirical Study on Pricing Model for Software Operation (소프트웨어 운영 대가산정 방식에 대한 실증적 연구)

  • Kim, Heungshik;Kim, Choong Nyoung;Seo, Yongwon
    • Journal of Information Technology Services
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    • v.18 no.4
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    • pp.67-82
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    • 2019
  • The purpose of this study is to improve the calculation method of the software operation pricing proposed by the software business price calculation guide from 'input manpower method' to 'rate calculation method'. The software operation pricing of the input manpower method is not objectively calculated in the domestic IT outsourcing situation where the statistical data based on the activity based estimating is insufficient and it is decided by agreement between the owner and the client. In addition, there was no standard for adjusting the productivity according to the characteristics of the operation service. In order to improve this, an operational correction factor item that can affect the software operation productivity was selected based on foreign and domestic standards, and it was confirmed through the first questionnaire to IT operation managers. In order to determine the level of difficulty of the fixed operational correction factors, the operational correction factor using AHP technique was confirmed through a second questionnaire for pairwise comparison. The operational difficulty calculation table was developed with reference to COCOMO and ITIL standards. Finally, we propose a new pricing scheme that reflects the operating rate. Regression analysis was carried out by collecting the data of the domestic public institutions on the estimated cost and the actual cost calculated from the new rate method software operation pricing. The results of the regression analysis show that the estimated cost and the actual cost are related to each other. Mean magnitude of relative error(MMRE) and PRED[25] analysis were added for accuracy analysis. MMRE and PRED also showed satisfactory results, confirming the possibility of replacing the rate method software operation pricing.

Omnichannel's Perception Effect on Omnichannel Use and Customer-Brand Relationship (옴니채널의 지각된 편리성과 유용성이 옴니채널 사용과 소비자-브랜드 관계에 미치는 영향)

  • Yim, Duk-Soon;Han, Sang-Seol
    • Journal of Distribution Science
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    • v.14 no.7
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    • pp.83-90
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    • 2016
  • Purpose - This study focuses on new type distribution channel that named as Omnichannel. Omnichannel is developed from Multichannel which is used in many distribution channels to buy or selling goods. Omnichannel basically needs an Information and Communications Technologies(ICT) to use, so researcher conduct a Technology Acceptance Model(TAM) to research model. Customer-brand relationship was used as dependent variable to focus on the role of Omnichannel. Research design, data, and methodology - The subject of this study is customer who purchase goods or service through omnichannel. Based on the literature from the preceding research analysis of TAM and customer-brand relationship, this study was constructed by the reference to previous studies, final research model design for figure out casual relationship among perceived ease of use, perceived usefulness, omnichannel use and customer-brand relationship. From 2016 February 3 to March 17, questionnaire survey targeted customers who use online and offline channels. 273 questionnaire survey had conducted, then, 252 survey data were available for empirical analysis. Researcher provide descriptive statistics for checking generality. Cronbach's alpha value was used to check the reliability of data. Exploratory factor analysis was used for purification of values and eigenvalue checking. After EFA, Confirmatory factor analysis was used to prepare structural equation modeling with executing structural equation modeling for confirming hypothesis which developed by researcher. Results - The main results of this empirical study are as follows. First, omnichannel's perceived ease of use has positive significant effect on perceived usefulness(estimate: 0.579). Moreover, omnichannel's perceived ease of use and perceived usefulness has positive significant effect on omnichannel use(estimate: 0.325,0.648). Second, using omnichannel has positive significant effect on brand-customer relationship(estimate: 0.521). Every hypothesis adopted as researcher designed. This study found out the intermediate relationship between perceived ease of use and omnichannel use by investigating hypothesis. Conclusions - Base on the empirical result, this study confirmed that TAM theory perceived has relation with omnichannel. First, factors of TAM has positive effect on omnichannel use, so it highlights the important role of customer based interface and usefulness. Especially, perceived usefulness has high indirect influence on ease of use and use of omnichannel. It seems that when customers try to decide use or not use omnichannel, customers focus on percept benefits from omnichannel. Thus, a provider should applicate attractive price table, accurate product or service information and high switching cost strategy to emphasize the usefulness of omnichannel. Second, using omnichannel enhances the relationship between customers and brand, because there are more time and frequency to serve customers. It is important because good relationship between customers can increase the future's financial performance through word of mouse, positive brand image and loyalty to brand or company. Finally, despite of empirical result and implications, this study has limitations. First, there are only a few previous studies about omnicahnnel, so literature reviews are restricted. While set up the factors which can affect the use of omnichannel, next study should be considered with broader theories or models(ex: contingency theory). Second, omnichannel has developed from multichannel, so comparative analysis is needed between these methods because there is a possibility about different forte character of each distribution system on customer's consuming patterns.

A Study on HL7 Communication Method for Acquisition of real-time Medical Data in Smart health-care Environment (스마트 케어 환경에서 실시간 의료데이터 획득을 위한 HL7 전송 방법에 대한 연구)

  • Jeon, Jae-Hwan;Kang, Sung-In;Kim, Gwan-Hyung;Choi, Sung-Wook;Oh, Am-Suk
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.05a
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    • pp.799-802
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    • 2012
  • 본 논문은 기존의 헬스케어 서비스의 한계를 극복하기 위해 최근 대두되고 있는 스마트 헬스케어 서비스(smart healthcare service)에 관한 연구이다. 스마트 헬스케어는 스마트폰의 기능에 맞추어 기초체력 운동 지수, 섭취 칼로리, 심박 체크 등의 다양한 서비스를 제공할 수 있지만, 최근에는 보건의료서비스에 특화시켜 환자와 의사가 직 간접적으로 진료를 할 수 있게끔 하는 스마트폰 환경에서의 원격진료 서비스가 부각되고 있다. 그러나 헬스케어를 위한 HL7 CDA 표준의 문서 교환방식은 실시간 데이터 획득을 요구하는 원격진료 서비스 환경에 적합하지 못하다. 이에 본 논문에서는 HL7v2.x의 트리거 이벤트를 통한 메시지 전송방식과 HL7 CDA RIM(Reference Information Model)을 응용하는 실시간 HL7 의료정보 전송 방안을 제안한다.

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Temperature effect analysis of a long-span cable-stayed bridge based on extreme strain estimation

  • Yang, Xia;Zhang, Jing;Ren, Wei-Xin
    • Smart Structures and Systems
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    • v.20 no.1
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    • pp.11-22
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    • 2017
  • The long-term effect of ambient temperature on bridge strain is an important and challenging problem. To investigate this issue, one year data of strain and ambient temperature of a long-span cable-stayed bridge is studied in this paper. The measured strain-time history is decomposed into two parts to obtain the strains due to vehicle load and temperature alone. A linear regression model between the temperature and the strain due to temperature is established. It is shown that for every $1^{\circ}C$ increase in temperature, the stress is increased by 0.148 MPa. Furthmore, the extreme value distributions of the strains due to vehicle load, temperature and the combination effect of them during the remaining service period are estimated by the average conditional exceedance rate approach. This approach avoids the problem of declustering of data to ensure independence. The estimated results demonstrate that the 95% quantile of the extreme strain distribution due to temperature is up to $1.488{\times}10^{-4}$ which is 2.38 times larger than that due to vehicle load. The study also indicates that the estimated extreme strain can reflect the long-term effect of temperature on bridge strain state, which has reference significance for the reliability estimation and safety assessment.

Readers' Advisory and Bibliotherapy in Korean Library Community (한국 도서관계에서 독자상담과 독서치료의 의미)

  • Lee, Jae-Whoan
    • Journal of Korean Library and Information Science Society
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    • v.40 no.4
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    • pp.5-29
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    • 2009
  • This article intends to discuss about the strategies and methods that the Korean library community should follow to make the ongoing experiment of 'bibliotherapy program' be successful, and eventually, settle up as a regular library service program. The main focus of discussion was on figuring out both theoretical foundations and historical roots that can justify such an experiment in Korean libraries. To the end, a comparative analysis to Readers' Advisory Services was conducted, and also done for comparing the special features in Korean libraries with those of American libraries, especially as related to library services to readers. The final suggestion includes the tasks that Korean LIS scholars should undertake to make the ongoing bibliotherapy experiment become an indigenous Korean model for library services.

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Pressure control of hydraulic servo system using proportional control valve (비례전자밸브를 사용한 유압서보계의 압력제어)

  • Yang, Kyong-Uk;Oh, In-Ho;Lee, Ill-Yeong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.8
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    • pp.1229-1240
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    • 1997
  • The purpose of this study is to build up control scheme that promptly control pressure in a hydraulic cylinder having comparatively small control volume, using a PCV (proportional control valve) and a digital computer. Object pressure control system has the character to be unstable easily, because the displacement-flow gain of the PCV is too large considering the small volume of the hydraulic cylinder and the time delay of response of the PCV is comparatively long. Considering the above-mentioned characteristics of the object pressure control system, in this study, control system is designed with two degree of freedom control scheme that is composed by adding a feed-forward control path to I-PDD$^{2}$ control system, and a reference model is used on the decision of control parameters. And through some experiments on the control system with FF-I-PDD$^{2}$ controller, the validity of this control method has been confirmed.

Development of Precise Point Positioning Method Using Global Positioning System Measurements

  • Choi, Byung-Kyu;Back, Jeong-Ho;Cho, Sung-Ki;Park, Jong-Uk;Park, Pil-Ho
    • Journal of Astronomy and Space Sciences
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    • v.28 no.3
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    • pp.217-223
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    • 2011
  • Precise point positioning (PPP) is increasingly used in several parts such as monitoring of crustal movement and maintaining an international terrestrial reference frame using global positioning system (GPS) measurements. An accuracy of PPP data processing has been increased due to the use of the more precise satellite orbit/clock products. In this study we developed PPP algorithm that utilizes data collected by a GPS receiver. The measurement error modelling including the tropospheric error and the tidal model in data processing was considered to improve the positioning accuracy. The extended Kalman filter has been also employed to estimate the state parameters such as positioning information and float ambiguities. For the verification, we compared our results to other of International GNSS Service analysis center. As a result, the mean errors of the estimated position on the East-West, North-South and Up-Down direction for the five days were 0.9 cm, 0.32 cm, and 1.14 cm in 95% confidence level.

Design and Implementation of DGPS device-based on Smart Phone (스마트폰 기반의 DGPS 단말 설계 및 구현)

  • Bang, Sungmin;Hong, Sungsu
    • KIISE Transactions on Computing Practices
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    • v.21 no.12
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    • pp.798-803
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    • 2015
  • DGPS is a technology that can improve the positioning precision of the existing GPS based on the correction information regarding reference station. Although the country is currently building infrastructure for DGPS correction information to be transmitted, it is being used only in limited areas for which DGPS expensive equipment is required. By enabling the development of the DGPS device using the smart phone, this limitation can be overcome, DGPS can be applied for various location-based services, and the implementation of the new model of location-based services may be enabled. In this paper, we introduce the development of a DGPS device for which high-precision positioning is possible using DGPS correction information received via the DMB network or mobile network in the smart phone environment.