• Journal of Korean Society for Quality Management
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• v.34 no.4
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• pp.78-92
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• 2006

While many services appear, it are performed in the various researches about a service. Among them, as to the basic reason for measuring the service level, in order to find out the strategy improving service quality. But the method for measuring quality of services up to date was unable to make it enough the role. This research tried to propose the approach systematically analyzing the human errors in order to improve service quality about the call center which utilizes the information technology. In fact, the human errors was found in the customer contact point in which the actual service is delivered. An interaction between the element for comprising call service was classified into 3 while defining the human error as 3 group. Moreover, the process where a service is delivered was classified according to 5 step and the generated error was measured in each step. The implication of this research looks at the service failure and dissatisfaction as the occurrence of the human errors and illustrates the service quality improvement as a correction or a reduction. This approach is used that service is materially easily understood and is formulated with the quality improvement strategy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.6
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• pp.540-549
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• 2013

An adaptive non-uniform quantization scheme is proposed for soft-decision error correction in NAND flash memory. Even though the conventional maximizing mutual information (MMI) quantizer shows the optimal post-FEC (forward error correction) bit error rate (BER) performance, this quantization scheme demands heavy computational overheads due to the exhaustive search to find the optimal parameter values. The proposed quantization scheme has a simple structure that is constructed by only six parameters, and the optimal values of them are found by maximizing the mutual information between the input and the output symbols. It is demonstrated that the proposed quantization scheme improves the BER performance of soft-decision decoding with only small computational overheads.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.3
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• pp.206-216
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• 2019

This study is aimed to compare stock assessment models depending on how the models fit to observed data. Process-error model, Observation-error model, and Bayesian state-space model for the Korean Western coast fisheries were applied for comparison. Analytical results show that there is the least error between the estimated CPUE and the observed CPUE with the Bayesian state-space model; consequently, results of the Bayesian state-space model are the most reliable. According to the Bayesian State-space model, potential yield of fishery resources in the West Sea of Korea is estimated to be 231,949 tons per year. However, the results show that the fishery resources of West Sea have been decreasing since 1967. In addition, the amounts of stock in 2013 are assessed to be only 36% of the stock biomass at MSY level. Therefore, policy efforts are needed to recover the fishery resources of West Sea of Korea.

• Asia Pacific Journal of Corpus Research
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• v.2 no.1
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• pp.23-34
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• 2021

This research examines Japanese non-native speakers' (JNNS) modal auxiliary verb use from two different perspectives: frequency of use and preferences for modalities. Additionally, error analysis is carried out to identify errors in modal use common among JNNSs. Their modal use is compared to that of English native speakers within a spoken dialogue corpus which is part of the International Corpus Network of Asian Learners' English. Research findings show at a statistically significant level that when compared to native speakers, JNNSs underuse past forms of modals and infrequently convey epistemic modality, indicating the possibility that JNNSs fail to express their opinions or thoughts indirectly when needed or to convey politeness appropriately. Error analysis identifies the following three types of common errors: (1) the use of incorrect tenses of modal verb phrases, (2) the use of inflected verb forms after modals, and (3) the non-use of main verbs after modals. The first type of error is largely because JNNSs do not master how to express past meanings of modals. The second and third types of errors seem to be due to first language transfer into second language acquisition and JNNSs' overgeneralization of the subject-verb agreement rules to modals respectively.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.1
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• pp.104-111
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• 2000

It is very difficult to maintain the desired tank level without any overflow or any shortage in a dangerous shemical plant and in a cooling one. Futhermore, because its dynamics are very complicate and nonlinear, it is impossible to realize the precise control using the accurate mathematical model which can be applied to the various peration modes. Nonetheless, the sliding mode controller(SMC) is known as having the robust variable structures for the nonlinear control system with the parametric perturbations and with the rapid disturbances. But the adaptive tuning algorithms for their parameters are not satisfactory. Therefore, in this paper, a Real Variable Elitist Genetic Algorithm based Sliding Mode Controller (RVEGA SMC) for the precise control of the coupled tank level was tried. The SMC's switching parameters were optimized easily and rapidly by RVEGA. The simulation results showed that the tank level could be satisfactorily controlled without and overshoot and any steady-state error by the proposed RVEGA SMC.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.239-244
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• 2002

Even though, tanks are used at the many industry plants, it is very difficult to control the tank level without any overflow and shortage; moreover, cause of its complication of dynamics and nonlinearity, it's impossible to realize the accurate control using the mathematical model which can be applied to the various operation modes. However, the sliding mode controller(SMC) is known as having the robust variable structures for the nonlinear control systems with the parametric perturbations and with the sudden disturbances, but the auto-tuning of parameters was a problem. Therefore, in this paper, a Genetic Algorithm based Sliding Mode Controller (GA-SMC) for the precise control of the coupled tank level was tried. GA optimized the SMCs switching parameters easily and rapidly. The simulation results are shown that the tank level could be satisfactorily controlled with less overshoot and steady-stale error by the proposed GA-SMC.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.7
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• pp.337-345
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• 2006

This paper proposes a high speed SRM drive system for blower application with a new 4-level inverter and precise excitation position generator. For a high speed blower, a proper inverter and control method are proposed and the output characteristics are analyzed. In order to get a fast build-up and demagnetization of excitation current, a 4-level inverter system is proposed. The proposed 4-level inverter has additional charge capacitor, power switch and diode in the conventional asymmetric converter. The charged high voltage is supplied to the phase winding for fast current build-up, and demagnetization current is charged to additional capacitor of the 4-level inverter. In addition, a precise excitation position generator can reduce turn-on and turn-off angle error according to sampling period of digital control system. The proposed high speed SRM drive system is verified by computer simulation and experimental results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.371-376
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• 2003

The objective of this paper is to compare the site-to-site variability of ISO 10844 pass-by-noise test sites. In order to investigate the site-to-site variance of test surfaces, European commercial tires are tested at seven different test sites. Three Korea test sites and four Europe test sites are selected.. The pass by noise test is executed according to a 2001/43/EC regulation. A]though the ISO surface has a very specific track composition, it does not reduce the variation of pass-by-noise measurements over the surface of test sites. This paper shows that the test results of pass-by-noise level are different depending on the test sites. The correlation obtained in this work is able to predict the pass by noise level for certain test site using the data measured from another test site. 17he prediction value is range with an error within 1dB(A).

• Journal of Preventive Medicine and Public Health
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• v.47 no.5
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• pp.273-280
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• 2014

Objectives: To evaluate the occurrence of patient adverse events in Korean hospitals as perceived by nurses and examine the correlation between patient adverse events with the nurse practice environment at nurse and hospital level. Methods: In total, 3096 nurses working in 60 general inpatient hospital units were included. A two-level logistic regression analysis was performed. Results: At the hospital level, patient adverse events included patient falls (60.5%), nosocomial infections (51.7%), pressure sores (42.6%) and medication errors (33.3%). Among the hospital-level explanatory variables associated with the nursing practice environment, 'physician-nurse relationship' correlated with medication errors while 'education for improving quality of care' affected patient falls. Conclusions: The doctor-nurse relationship and access to education that can improve the quality of care at the hospital level may help decrease the occurrence of patient adverse events.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.321-328
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• 2016

Typical MLC NAND flash devices are considered less reliable than SLC NAND flash devices. Although raw bit error rate (RBER) of MLC flash had been considered approximately 1000times or more higher than that of SLC flash, recent research conducted on Google's data center shows that it is much lower than such expectation. Based on the research, we devised In Drive Data Duplication (IDDD) scheme that efficiently exploit MLC flash's sufficient capacity to improve its data reliability without structural complexity increment using SSD intrinsic firmware layer, and showed the data reliability expectation of MLC flash could be significantly higher than that of SLC flash from measured and calculated error rates. Even though RBER of SLC flash was lower than that of MLC flash in 44 out of 48 cases we studied, applying IDDD scheme, RBER of MLC flash was became lower than that of SLC in all 48 cases and uncorrectable bit error rate (UBER) of MLC flash was became lower than that of SLC flash in 45 out of 48 cases.