• Journal of Information Processing Systems
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• v.11 no.3
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• pp.389-405
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• 2015

Most traditional database systems exploit a record-oriented model where the attributes of a record are placed contiguously in a hard disk to achieve high performance writes. However, for read-mostly data warehouse systems, the column-oriented database has become a proper model because of its superior read performance. Today, flash memory is largely recognized as the preferred storage media for high-speed database systems. In this paper, we introduce a column-oriented database model based on flash memory and then propose a new column-aware flash indexing scheme for the high-speed column-oriented data warehouse systems. Our index management scheme, which uses an enhanced $B^+$-Tree, achieves superior search performance by indexing an embedded segment and packing an unused space in internal and leaf nodes. Based on the performance results of two test databases, we concluded that the column-aware flash index management outperforms the traditional scheme in the respect of the mixed operation throughput and its response time.

• Journal of Information Technology Applications and Management
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• v.16 no.1
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• pp.77-96
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• 2009

The balanced scorecard has drawn attention from many researchers in various fields since its appearance in 1992. It became a norm for performance evaluation framework in many areas, such as marketing, information system evaluation, strategic planning, etc. Centered in the large companies in Korea, the balanced scorecard has been popularly used as a performance evaluation tool for human resource management. Now we Question its applicability to performance evaluation tool even in small business. This study tried to apply the balanced scorecard in developing an information system for performance evaluation in a small business. The study showed that the balanced scorecard can be nicely used in small business as a performance evaluation tool. The process of developing an information system is described in detail. The practitioners are to obtain a lot of insights in designing their human resource management systems from the study results.

• Asia pacific journal of information systems
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• v.13 no.1
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• pp.1-22
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• 2003

This study describes how the weights of performance measures varies depending on business strategy types, such as defenders, prospectors, analyzers, and reactors. A Balanced Scorecard has been widely used for measuring a corporate performance to incorporate financial and non-financial measures simultaneously. Because such performance measurements are related to the compensation and promotion of employees, research of weights of performance measures would be instrumental. Our test results demonstrate that the weights of the business performance measures differ in the four perspectives-financial, customer, internal process, and learning and growth. Furthermore, there is evidence that the weights of performance measures vary depending on business strategy. Our study results can be used for enhancing the quality of performance measurement systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.7
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• pp.2435-2453
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• 2015

Independent component analysis (ICA) is a signal processing technique used for un-mixing of the mixed recorded signals. In wireless communication, ICA is mainly used in multiple input multiple output (MIMO) systems. Most of the existing work regarding the ICA applications in MIMO systems assumed static or quasi static wireless channels. Performance of the ICA algorithms degrades in case of time varying wireless channels and is further degraded if the data block lengths are reduced to get the quasi stationarity. In this paper, we propose an ICA based MIMO transceiver that performs well in time varying wireless channels, even for smaller data blocks. Simulation is performed over quadrature amplitude modulated (QAM) signals. Results show that the proposed transceiver system outperforms the existing MIMO system utilizing the FastICA and the OBAICA algorithms in both the transceiver systems for time varying wireless channels. Performance improvement is observed for different data blocks lengths and signal to noise ratios (SNRs).

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.4
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• pp.132-138
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• 2008

Small and medium-sized manufacturing companies have introduced production information systems such as pop and MES to improve their productivity. However, there has been little research on this field This study provides answers for 3 following critical questions for successful implementation of production information systems based on the literature review and case studies. First, do investments on this system bring the positive performance? Second, what are the critical success factors that should be managed? Third, how long does it take to obtain its performance? This paper suggests some implications for the practitioners.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.11
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• pp.5305-5321
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• 2016

In wireless communication, the multiple-input multiple-output (MIMO) system is a well-known approach to improve the reliability as well as the data rate. In MIMO systems, channel state information (CSI) is typically required at the receiver to detect transmitted signals; however, in practical systems, the CSI is imperfect and contains errors, which affect the overall system performance. In this paper, we propose a novel maximum likelihood (ML) scheme for MIMO systems that is robust to the CSI errors. We apply an optimization method to estimate an instantaneous covariance matrix of the CSI errors in order to improve the detection performance. Furthermore, we propose the employment of the list sphere decoding (LSD) scheme to reduce the computational complexity, which is capable of efficiently finding a reduced set of the candidate symbol vectors for the computation of the covariance matrix of the CSI errors. An iterative detection scheme is also proposed to further improve the detection performance.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.373-377
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• 2001

This study is to examine the factors that influence the performances of service quality in university hospitals by investigating systematically the condition of service quality. A synthesis of the health care quality is conducted to identify physical quality, operating process quality, and human resources quality that relate to both the overall satisfaction and intention of revisit. Based on the proposed hypotheses, the relationships between the service quality factors and performance are examined using data collected from 167 patients in three hospitals, Korea. Reliability and validity tests are performed for examining its relationship with service quality in health care systems. Total eight independent variables with respect to three service quality levels and two dependent variables for performance are identified for relationships between service quality and performance in health care systems. The results provide health care managers with a managerial insight to the planning function of performance with service quality in health care systems as well as other operations (business, government, or other service organizations) systems. Implication of the study for theory, future studies, and practices are discussed.

• Journal of information and communication convergence engineering
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• v.7 no.3
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• pp.286-291
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• 2009

In this paper, the performance of ultra-wideband (UWB) single input multiple output (SIMO) systems to achieve high data rate communications is studied in dense multipath environments. The effects of spatial and temporal diversities on the performance of multi-user time-hopping UWB systems using binary pulse position modulation (2PPM) are analyzed. The reduced-complexity Rake receivers based on the selective combining (called SRake) and partial combining (called PRake) are considered. The theoretical and simulation results show that the BER performance of the UWB system can be enhanced as the number of array elements and/or Rake fingers increases. Moreover, we observe that SRake is more effective for the IR-UWB systems to achieve a good BER performance, as compared with PRake.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.2
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• pp.193-200
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• 2002

A study was conducted to investigate the availability of Fitts' Law to Hangul input systems on mobile phones. Three different Hangul input systems were experimented to measure the performance time to evaluate the physical interface of all. The measured performance time was found to be well fitted with the modified Fitts' Law by Hangul input systems on mobile phones. As a result, the physical interfaces for Hangul input systems could be evaluated quantitatively with the prediction of the performance time by Fitts' Law.

• Management & Information Systems Review
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• v.3
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• pp.1-14
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• 1999

Recently, information resource management(IRM) has a considerable interest among researchers and practitioners because the information resource have been found critical influence on organizational performance. The IRM construct has been defined a comprehensive approach to planning, organizing, controlling the resources, and activities associated with acquiring and distributing data to meet a business need. This study have several objectives: 1) to operationalize the measurement instrument of IRM, 2) to identify the factors influencing organizational performance, and 3) to suggest the research model between IRM and organizational performance and then 4) to provide reference for managers to assess the IRM implementation in their organization. By reviewing the literature, past experience, others' use, encouragement by others, and anxiety are selected as the factors influencing IRM. The IRM construct has been classified with eight dimensions : chief information officer, planning, security, technology integration, advisory committees, enterprise model, information integration, and data administration. Eight hypotheses concerning the relationship between each of the IRM and organizational performance are suggested in this study.