• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11A
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• pp.862-869
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• 2009

We propose a new adaptive K-best Sphere Decoding (SD) algorithm for Multiple Input Multiple Output (MIMO) systems where the number of survivor paths, K is changed based on the characteristics of path metrics which contain the instantaneous channel condition. In order to overcome a major drawback of Maximum Likelihood Detection (MLD) which exponentially increases the computational complexity with the number of transmit antennas, the conventional adaptive K-best SD algorithms which achieve near to MLD performance have been proposed. However, they still have redundant computation complexity since they only employ the channel fading gain as a channel condition indicator without instantaneous Signal to Noise Ratio (SNR) information. hi order to complement this drawback, the proposed algorithm use the characteristics of path metrics as a simple channel indicator. It is found that the ratio of the minimum path metric to the other path metrics reflects SNR information as well as channel fading gain. By adaptively changing K based on this ratio, the proposed algorithm more effectively reduce the computation complexity compared to the conventional K-best algorithms which achieve same performance.

• Journal of Communications and Networks
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• v.6 no.2
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• pp.93-105
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• 2004

This paper discusses cyclostationary interference suppression for multiuser wired communication systems. Crosstalk interference from digital signals in multipair cables has been shown to be cyclostationary. Many crosstalk equalization or suppression techniques have been proposed which make implicit use of the cyclostationarity of the crosstalk interferer. In this paper, the convergence and steady-state behaviors of a fractionally spaced equalizer (FSE) in the presence of multiple cyclostationary crosstalk interference are thoroughly analyzed by using the equalizer's eigenstructure. The eigenvalues with multiple cyclostationary interference depend upon the folded signal and interferer power spectra, the cross power spectrum between the signal and the interferer, and tile cross power spectrum between the interferers, which results in significantly different initial convergence and steady-state behaviors as compared to the stationary noise case. The performance of the equalizer varies depending on the relative clock phase of the symbol clocks used by the signal and multiple interferers. Measued characteristics as well as analytical model of NEXT/FEXT channel are used to compute the optimum and worst relative clock phases among the signal and multiple interferers.

• Korean Journal of Child Studies
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• v.38 no.3
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• pp.75-90
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• 2017

Objective: This study aimed to identify children's cognitive processing and performance characteristics while multiple task performance. It confirmed whether their multiple task performance and psychological refractory period (PRP) varied by task condition (stimulus onset asynchrony [SOA] and task difficulty) and stimulus modality. Methods: Seventy 5-year-olds were recruited. Multi-task tools were developed using the E-prime software. The children were required to respond to two stimuli (visual or auditory) presented with microscopic time difference and their response times (RTs) were recorded. Results: As the SOA increased, the RTs in the first task increased, while the RTs in the second task and PRP decreased. The RTs of the first and second tasks, and the PRP for difficult tasks, were significantly longer than those for easy tasks were. Additionally, there was an interaction effect between the SOA and task difficulty. Although there was no main effect of stimulus modality, task difficulty moderated the modality effect. In the high difficulty condition, the RTs of the first and second tasks and PRP for the visual-visual task were significantly longer than those for auditory-auditory task were. Conclusion: These results inform theoretical discussions on children's multi-task mechanism, and the loss of multiple task performance. Additionally, they provide practical implications and information on the composition of multi-tasks suitable for children in educational environments.

• Asia-Pacific Journal of Business
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• v.3 no.1
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• pp.29-38
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• 2012

This study aims at evaluating the impact of network formation variables and found to have positive impact on the economic performance and growth of the enterprises. The calucation of the weighted scores of networking statements brought some affirmative results to influence the performance of the enterprises. Through multiple regression and logistic regression models it is identified that network formation variables like service receiving status, consultation of the family, other business dummy and attendance in fair have some significant positive impact both on the growth and performance of the enterprises. In addition to above variables, from the set of enterprise characteristics natural logarithm of the market value of total assets and from the entrepreneurs' characteristics set of variables, schooling year and squared value of the experience have been found to have significant positive impact. Finally, it is concluded in the study that to enhance the performance and growth of the enterprises, government and policy rlated organizations need to consider important variables that have positive impact in supplying the entrepreneurial resources especially, developing the net-working relationship.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.3
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• pp.471-479
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• 2019

This research proposes a indoor magnetic map matching algorithm that improves the position accuracy by employing multiple magnetic sensors and probabilistic candidate weighting function. Since the magnetic field is easily distorted by the surrounding environment, the distorted magnetic field can be used for position mapping, and multiple sensor configuration is useful to improve mapping accuracy. Nevertheless, the position error is likely to increase because the external magnetic disturbances have repeated pattern in indoor environment and several points have similar magnetic field distortion characteristics. Those errors cause large position error, which reduces the accuracy of the position detection. In order to solve this problem, we propose a method to reduce the error using multiple sensors and likelihood boundaries that uses human walking characteristics. Also, to reduce the maximum position error, we propose an algorithm that weights according to their importance. We performed indoor walking tests to evaluate the performance of the algorithm and analyzed the position detection error rate and maximum distance error. From the results we can confirm that the accuracy of position detection is greatly improved.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.31-37
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• 2008

In this paper, we propose a dynamic job relocation strategy that considering application's characteristics in multiple grid sites. This scheme classifies application to execute in multiple grid sites by their characteristics : computing intensive application, network intensive application. Also, it eliminates the communication between sites by allocating the network intensive application in single site, thus reducing the total job execution time. But if a number of free nodes to execute the network intensive application aren't found in single site, the proposed scheme the first allocates the network intensive application in multiple sites to minimize network latency. Then if the network intensive application being executed in multiple sites suitable free nodes are found in single site. the proposed scheme relocates the application being executed in multiple sites to another single site. This results in reducing the total job execution time. Through simulation, we show that the proposed dynamic job reallocation strategy improves the performance of Data Grid environment compared with previous strategies.

• The Korean Journal of Emergency Medical Services
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• v.20 no.3
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• pp.69-83
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• 2016

Purpose: The purpose of this study was to explore the factors influencing evidence-based fall prevention nursing performance of hospital nurses. Methods: A self-reported questionnaire was completed by 344 nurses from three general hospitals from January 20 to March 10, 2013. The study instruments included general characteristics of the subjects, and awareness and performance of fall prevention. Data were analyzed by t test, ANOVA, Pearson's correlation, and multiple regression using SPSS v. 20.0. Results: There were statistically significant differences in awareness and performance according to age, marital status, clinical experiences, workplace, experience of fall prevention education, knowledge of fall prevention, compliance with fall prevention, attention level toward prevention, recognition level of potential falls, nurse responsibility for falls, importance of fall prevention, efforts level for fall prevention, and awareness score of falls prevention. There was a positive correlation among awareness and performance of fall prevention. Based on the multiple regression analysis, compliance with fall prevention, efforts level for fall prevention, and awareness score of falls prevention were significant predictors for performance of fall prevention. The explanation power of the model was 64.1%. Conclusion: The findings revealed the need to develop an effective nursing intervention to improve hospital nurses' performance for fall prevention.

• Journal of Intelligence and Information Systems
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• v.10 no.2
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• pp.133-145
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• 2004

Combining multiple classifiers to obtain improved performance over the individual classifier has been a widely used technique. The task of constructing a multiple classifier system(MCS) contains two different issues : how to generate a diverse set of base-level classifiers and how to combine their predictions. In this paper, we review the characteristics of the existing multiple classifier systems: bagging, boosting, and stacking. And then we propose new MCSs: stacked bagging, stacked boosting, bagged stacking, and boasted stacking. These MCSs are a sort of hybrid MCSs that combine advantageous characteristics of the existing ones. In order to evaluate the performance of the proposed schemes, we conducted experiments with nine different real-world datasets from UCI KDD archive. The result of experiments showed the superiority of our hybrid MCSs, especially bagged stacking and boosted stacking, over the existing ones.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.1
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• pp.116-127
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• 2000

This study investigated the effects of sales supervisors on salespeople's goal orientations and sales performance in fashion retail setting. Specifically, it examined: 1) the differences in salespeople's goal orientations by salespeople characteristics; 2) the effects of supervisor's behavioral orientations on goal orientations of salespeople; and 3) the effects of salespeople's goal orientations on performance. A total of 343 questionnaires collected from salespeople in various apparel and accessory selling departments at four department stores in Korean were analyzed. Variables included supervisor's behavioral orientations(end-results, activity and capability), salespeople's goal orientations(learning and performance), sales performance and salespeople characteristics. MANOVA revealed that three was no difference in goal orientations by salespeople characteristics except by selling department. Multiple regression analysis revealed that supervisor's end-result orientation affected salespeople's learning orientation and performance orientation while activity and capability orientations did not. The study suggests that for long-term performance supervisors and retail organizations need to develop various supervisory behaviors, stimulate learning demands of salespeople, and provide training programs to achieve the learning goal.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.8
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• pp.1958-1969
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• 1996

This paper proposed a new approach to adaptive call admission control based on a neural network for multiple service classes with different quality of service (QoS) in the ATM-based Broadband Integrated Services Digital Networks. the proposed method extend Hiramatsu's neural network based "leaky pattern table" method for the single QoS[1, 2, 3] to deal with multiple services with different QoS by constructing multiple pattern tables based on each service's acceptance or rejection at the call set-up requests, and by simultaneously controlling each service's QoS according to the target QoS of the service and the trunk capacity. Computer simulation results on two service classes with different traffic characteristics and different cell loss rates as QoS, highlight good performance and effectiveness of the proposed call admission controller for multiple service classes.e classes.