• Journal of Korean Institute of Industrial Engineers
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• v.35 no.1
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• pp.51-57
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• 2009

There are a variety of users and devices in a context-aware computing environment. In this environment, the service provided to a user may be the composition of diverse services rather than one independent service. Before user's devices provide the composite service to the user, they should perceive user's needs by gathering related information segments from other surrounding devices and/or sensors. We consider a context-aware computing environment providing composite and adapted service to users and propose an information processing model that characterizes the device where the collected data should be processed through services and/or applications. Based on this model, we provide an analytical tool to obtain some performance measures of the context-aware computing environment.

• Journal of Information Technology Applications and Management
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• v.20 no.3_spc
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• pp.259-278
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• 2013

At the center of the repeating evolution of IT industry, there is mobile computing in the ubiquitous environment, and the increasing usage of smart phones contribute more to its growth. P corporation co-developed with Google and implemented smart work system called SWP for the purpose of 'communication and collaboration with co-workers' beyond the general goal of increasing productivity and comfort of employees. The primary objective of this study is to objectively analyze the influence of the effect factor from end user's perspective and user satisfaction on SWP usage, intention for continuous usage and individual performance. To accomplish this research purpose, this study established research models and hypothesis by collective review about information system success models, and tested the research hypotheses using the structural equation modeling technique by data collected from 320 SWP system users of P corporation. Variations for system satisfaction evaluation standard are 1)SW system usage 2) intention for continuous usage 3) individual performance, effect variations are 1) social factors 2) technical factors 3) combination of social and technical factors. Therefore, this study is about influence factors on success of SWP system and how the factors impact the outcome. The test results of this research model is summarized as follows. Firstly, system user's satisfaction had positive impact on all three; SWP system usage, intention for continuous usage and individual performance. Secondly, social factor 'SWP control system' and technical factor 'information quality' and 'system quality' had positive impact on SWP system user satisfaction, while social factor 'shared value' and technical factor 'service quality' did not have significant effect on user satisfaction. Shared value however, had interactive effect with 'information quality' and 'service quality'. This study is expected to contribute to spread of academic research on smart work system by suggesting a model that can show important factors for corporation while explaining the successful implementation of SWP and its continuous usage.

• Journal of Communications and Networks
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• v.12 no.4
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• pp.366-374
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• 2010

Coded cooperation is a promising user cooperation scheme. In this paper, we first propose a novel network-coding-based coded cooperation scheme. When a user decodes its partner's information correctly in the first frame, it transmits the combination of the partner's parity bits and its own parity bits through network coding in the second frame. This is distinct from the classical scheme, where the user only transmits the partner's parity bits during cooperation. We analyze the outage probability of the proposed scheme, and show that it achieves a full diversity order. Numerical evaluations reveal that the proposed scheme outperforms the classical scheme when the inter-user channel is poor, yet is worse when the inter-user channel is strong. Also, the results show that the proposed scheme always outperforms that of no cooperation in various channel conditions while the performance of classical scheme is worse than that of no cooperation with the poor inter-user channels. This means that the performance of the proposed scheme is more stable than the classical scheme and the proposed scheme is more tolerant to the poor inter-user channels. To combine the advantages of the proposed scheme and the classical scheme under different inter-user channel conditions, we propose an adaptive solution. This adaptive scheme enhances the system performance considerably in all channel conditions in spite of the inter-user channel quality, at the expense of only one acknowledgement or non-acknowledgement bit.

• The Transactions of the Korea Information Processing Society
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• v.4 no.8
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• pp.2038-2059
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• 1997

The physical attributes of a computer, such as processor speed, size and access time of memory, and I/O bandwidth, are fixed when the computer is delivered to the user. Under these conditions, the performance of a multi-process system where multiple processes share various resources can be enhanced by monitoring and controlling the relationship between the user processes and the system resources. This paper applies object oriented concept to the performance management and suggests a standard for the management. Resource managers and user processes are defined as managed object and a performance manager is defined as a managing object. A protocol between the user processes and performance manager is designed and attributes and methods of the objects are also defined. Through the standardization, the user processes and the performance manager can be developed independently and the system's performance can also be collectively managed.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.1
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• pp.99-104
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• 2014

Nowadays, various researches fulfill in many communication engineering area for B4G (Beyond Forth Generation). Next LTE-A (Long Term Evolution Advanced), MU-MIMO (Multi-User Multi Input Multi Output) method raises to upgrade throughput performance. However, the method of user selection is not decided because of many types and discussions in MU-MIMO system. Many existing methods are powerful for enhancing performance but have various restrictions in practical implementation. Fairness problem is primary restriction in this area. Existing papers emphasis algorithm to increase sum-rate but we introduce an algorithm about dealing with fairness problem for real commercialization implementation. Therefore, this paper introduces new user selection method in MU-MIMO system. This method overcomes a fairness problem in SUS (Semiorthogonal User Selection) algorithm. We can use the method to get a similar sum-rate with SUS and a high fairness performance. And this paper uses a hybrid method with SC-SUS (Superposition Coding SUS) algorithm and SUS algorithm. We find a threshold value of optimal performance by experimental method. We show this performance by computer simulation with MATLAB and analysis that results. And we compare the results with another paper's that different way to solve fairness problem.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.287-304
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• 2012

Spectrum sensing is an important functionality for cognitive users to look for spectrum holes before taking transmission in dynamic spectrum access model. Unlike previous works that assume perfect knowledge of the SNR of the signal received from the primary user, in this paper we consider a realistic case where the SNR of the primary user's signal is unknown to both fusion center and cognitive radio terminals. A Kalman filter based adaptive Takagi and Sugeno's fuzzy system is designed to make the global spectrum sensing decision based on the observed energies from cognitive users. With the capacity of adapting system parameters, the fusion center can make a global sensing decision reliably without any requirement of channel state information, prior knowledge and prior probabilities of the primary user's signal. Numerical results prove that the sensing performance of the proposed scheme outperforms the performance of the equal gain combination based scheme, and matches the performance of the optimal soft combination scheme.

• The Journal of the Korea Contents Association
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• v.17 no.2
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• pp.489-498
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• 2017

This study analyzed whether the suitability of strategy is playing a regulative role between IT characteristics & user characteristics and non-financial performance empirically. To this end, this study set up IT characteristics and user characteristics as independent variables, and set up non-financial performance as the performance variable of KMS, and also set up the suitability of the management strategy & informatization strategy of a business as moderating variables. This study defined the detailed factors in IT characteristics as IT maturity and IT/IS infrastructure while defining the detailed factors in user characteristics as perceived profit, organizing of learning, and user professionalism. In addition, this study defined non-financial performance as an organization member satisfaction, and KMS availability. As a result of the analysis, IT maturity & IT/IS infrastructure, which are defined as IT characteristics, and perceived profit, organizing of learning and user professionalism, etc., which were defined as user characteristics, were found to be variables playing a regulative role in non-financial performance.

• Journal of Information Technology Applications and Management
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• v.11 no.3
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• pp.117-135
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• 2004

The purpose of this research is to examination whether End-User Computing relative factors are ap-plied in Computer Assisted Reporting. Computer Assisted Reporting is closely related to End-User Computing, because IT and IS be used by reporting for data gathering and analysis. For the purpose, we've produced a survey, and then studied the effects of the use of Computer Assisted Reporting tools on the report's satisfaction and job performance. As a result, The degree of use of Computer Assisted Reporting significantly affects the degree of satisfaction and job performance. for this reason, this research can give an insight for the extension of End-User Computing relative research.

• Asia pacific journal of information systems
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• v.11 no.4
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• pp.155-173
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• 2001

This study identified CSFs(Critical Success Factors) for successful ERP system implementation in small and medium firms, and empirically tested relationship between CSFs and user performance. Survey questionnaires were distributed via email & fax to 142 firms that have implemented ERP systems. Out of 52 responded questionnaires, 46 data sets were available for statistical analysis with SPSSWin8.0. CEO's participation, vendor support & service, securing human resources, effective use of software, and hardware capacity were identified as CSFs from factor analysis. Among those factors, vendor support & service and effective use of software were related to user performance, and the relationship was shown to be statistically significant. Study results also showed that user performance of ERP system was significantly different among those surveyed firms when ERP system package products were used as a simple proxy measure of independent variable.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.396-409
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• 2023

In the field of autonomous vehicles, where high accuracy and reliability are critical, various satellite navigation augmentation systems have been developed to improve system performance. These systems generate correction and integrity information based on measurements and navigation data collected from ground reference stations, enhancing user positioning accuracy. Thus, the performance of the system heavily relies on the deployment and spacing of reference stations. To construct an effective satellite navigation augmentation system, careful consideration must be given to the installation points of reference stations. This paper presents a user positioning performance modeling formula and proposes a method for selecting the installation points of new reference stations. The proposed method involves selecting a candidate group area that can optimize the user's positioning performance. By utilizing this method, the system's performance can be improved, ensuring high accuracy and reliability for autonomous vehicle applications.