• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.2
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• pp.318-329
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• 1994

This paper deals with the finite wordlength effect on the performance of digital PID controllers. The finite wordlength, one of the major limitation factors in digital controllers, results on two kinds of quantization error : the signal quantization error and the coefficient quantization error. This paper derives the variance of the plant output due to the signal quantization error. Using stability margins as performance criterion, the statistical wordlength concept is adopted for coefficient wordlength selection. Finally, the experimental results exhibit satisfactory performance of the digital PID controller with statistical coefficient wordlength.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.373-376
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• 2002

This paper represents a survey of a variety thresholding techniques including both global and local thresholding. Several thresholding methods are examined in detail to evaluate their performance based on a given set of test images. We also attempt to evaluate the performance of several thresholding methods for construction field documents image recognition system using a broken line structures, broken symbols and text, blurring of lines, symbols and text, noise in homogeneous areas measure as a criterion functions.

• The Korean Journal of Nuclear Medicine
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• v.37 no.2
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• pp.103-109
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• 2003

Purpose: In patients with chronic knee pain, the diagnostic performance of $^{99m}Tc-MDP$ knee SPECT for internal derangement of knee is deteriorated due to degenerative changes. In this study, we tried to establish diagnostic criteria to differentiate medial meniscal injury (MMI) from degenerative change (DC) when the uptake is increased in medial compartment. Materials and Methods: A total of 49 knee SPECT of the patients with chronic (more than 3 months) knee pain, which showed increased $^{99m}Tc-MDP$ uptake in the medial compartment, were included in this study. The diagnosis was confirmed by arthroscopy. On knee SPECT, 3 diagnosic criteria for MMI were investigated. In Criterion I, MMI was diagnosed when crescentic uptake was observed in the medial tibial plateau. In Criterion II, crescentic uptake was further classified into anterior, mid, posterior, and diffuse patterns, according to the location of maximal uptake; and only crescentic mid, posterior, and diffuse patterns were diagnosed as MMI. In Criterion III, MMI was diagnosed when medial tibial plateau showed higher activity then medial femoral condyle. The diagnostic performance of the 3 criteria was compared. Results: The sensitivity and specificity were 93% and 14% in Criterion I, 89% and 38% in Criterion II, and 75% and 67% in Criterion III, respectively. Criterion III had significantly improved diagnostic performance, especially, specificity. Conclusion: In this study, we established a practical diagnostic criterion to differentiate MMI from DC on knee SPECT. The result is helpful to improve the diagnostic value of knee SPECT as a screening test for chronic knee pain.

• Journal of Information Technology Services
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• v.10 no.4
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• pp.171-189
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• 2011

KAs information and knowledge are increasingly becoming more important in the knowledge-driven society, knowledge management, as a very important management paradigm, is securing firm position in private and public sectors. Complying with this paradigm, government-funded research institutes in science-technology sector are actively utilizing knowledge management by employing knowledge management system and evaluating its applications' performance. The purpose of this study is to develop evaluation items and measurement indices to rationally measure knowledge management performance of the government-funded research institutes and to verify the feasibility of applying these evaluation items and indices. To achieve this research goal, the evaluation model of knowledge management performance was constructed by reviewing and integrating the existing studies, and subsequently, evaluation areas, evaluation items, measurement indices were derived from this evaluation model. Also, the feasibility analysis on the evaluation items and measurement indices was performed by means of FGI(Focus Group Interview) with the knowledge management experts belonging to Korean government-funded institutions in science-technology sector. The implications of this study are as follows : in theoretical perspective, this study has proposed a criterion frame to evaluate knowledge management performance, and has rationally drawn evaluation items and measurement indices from the criterion frame. And in practical perspective, this study has improved the validity and practicality of the measurement indices, which can lead to more reasonable and easier evaluation of knowledge management performance of the government-funded research institutes.

• Journal of the Korea Institute of Building Construction
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• v.5 no.2 s.16
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• pp.123-130
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• 2005

The purpose of this study is to present the optimum performance of hybrid waterproofing technology, which is including material and construction method. Recently, Hybrid waterproofing technology is developed little by little in KOREA. But there is not any other criterion of performance and evaluation of this technology. So, It is needed that appropriate performance items is are settled urgently. This paper were obtained by the SPSS analysis. In this study the safety factor are more important performance of building waterproofing materials than durability comfortability and productivity. And results of this analysis showed that (1) safety performance consists of Fatigue resistance, Crack Control performance deterioration Processing of tensile performance, Compressive Strength test (2) comfortability performance consists of watertightness, bond performance (3) persistency performance consists of abrasion resistance, tensile performance, flexural strength (4) productivity performance consists of dimension, unit space weight.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.6
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• pp.50-61
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• 2007

The structural stiffness, strength and stability on the bodyshell and floor structures of the Korean Low Floor Bus composed of laminate, sandwich panels and metal reinforced frame were evaluated. The laminate composite panel and facesheet of sandwich panel were made of WR580/NF4000 glass fabric/epoxy laminate, while aluminum honeycomb or balsa was applied to the core materials of the sandwich panel. A finite element analysis was used to verify the basic design requirements of the bodyshell and the floor structure. The use of aluminum reinforced frame and honeycomb core was beneficial for weight saving and structural performance. The symmetry of the outer and inner facesheet thickness of sandwich panels did not affect the structural integrity. The structural strength of the panels was evaluated using Von-Mises criterion for metal structures and total laminate approach criterion for composite structures. All stress component of the bodyshell and floor structures were safely located below the failure stresses. The total laminate approach is recommended to predict the failure of hybrid sandwich composite structures at the stage of the basic design.

• Communications for Statistical Applications and Methods
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• v.18 no.3
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• pp.343-355
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• 2011

For a data with the assumption of the mixture distribution, it is important to find an appropriate threshold and evaluate its performance. The relationship is found of well-known nine classification accuracy measures such as MVD, Youden's index, the closest-to-(0, 1) criterion, the amended closest-to-(0, 1) criterion, SSS, symmetry point, accuracy area, TA, TR. Then some conditions of these measures are categorized into seven groups. Under the normal mixture assumption, we calculate thresholds based on these measures and obtain the corresponding type I and II errors. We could explore that which classification measure has minimum type I and II errors for estimated mixture distribution to understand the strength and weakness of these classification measures.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.10
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• pp.3409-3422
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• 2014

The frequency spectrum available for the wireless communication is extremely crowded. In order to improve the spectral efficiency, the two-way relay networks have aroused great attention. A simple $N^{th}$ best-relay selection criterion for the opportunistic two-way relay networks is proposed, which can be implemented easily by extending the distributed timer technique in practice, since the proposed criterion is mainly based on the channel gains. The outage performance of the proposed relay selection scheme is analyzed under the outdated channel state information (CSI), and a tight closed-form lower bound and asymptotic value of the outage probability over Rayleigh fading channels are obtained. Simulation results demonstrate that the tight closed-form lower bound of the outage probability very closely matches with simulated ones in the whole SNR region, and the asymptotic results provide good tight approximations to the simulation ones, especially in the high SNR region.

• Research in Community and Public Health Nursing
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• v.31 no.2
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• pp.130-142
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• 2020

Purpose: The purpose of this study was to verify the validity and reliability of the Korean version of the Pain in Older Adults Knowledge Survey (K-POAKS) to assess knowledge of pain in older adults including people with dementia for use in long-term care hospital nurses. Methods: Survey data were collected from a convenience sample of 179 nurses who have worked in long-term care hospitals in B, D and U cities. The Kuder-Richardson Formula 20 for internal consistency for test reliability was conducted. The content, criterion-related and construct validity were evaluated using SPSS/WIN 22.0. Results: The KR 20 was .75 and Content Validity Ratio (CVR) was a range of 0.84~1.00. The criterion-related validity was positively correlated with attitudes (r=.28, p<.001) and performance (r=.21, p=.004). The construct validity of K-POAKS was analyzed by conducting the principal component method using the exploratory factor analysis varimax rotation, and seven factors were derived above the eigenvalue of 1.0. The seven factors explained 58.5% of the total variation. Conclusion: The Korean version of the POAKS showed satisfactory internal reliability, content validity, criterion-related validity and construct validity. These results suggest that the K-POAKS could be used as a suitable tool to measure the knowledge of the aged people's pain, including that of dementia patients for long-term care hospital nurses.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.123-126
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• 1995

Characteristics of control system design using Universal Learning Network (U.L.N.) are that a system to be controlled and a controller are both constructed by U.L.N. and that the controller is best tuned through learning. U.L.N has the same generalization ability as N.N.. So the controller constructed by U.L.N. is able to control the system in a favorable way under the condition different from the condition of the control system in learning stage. But stability can not be realized sufficiently. In this paper, we propose a robust control method using U.L.N. and second order derivatives of U.L.N.. The proposed method can realize better performance and robustness than the commonly used Neural Network. Robust control considered here is defined as follows. Even though initial values of node outputs change from those in learning, the control system is able to reduce its influence to other node outputs and can control the system in a preferable way as in the case of no variation. In order to realize such robust control, a new term concerning the variation is added to a usual criterion function. And parameter variables are adjusted so as to minimize the above mentioned criterion function using the second order derivatives of criterion function with respect to the parameters. Finally it is shown that the controller constricted by the proposed method works in an effective way through a simulation study of a nonlinear crane system.