• Health Policy and Management
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• v.27 no.1
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• pp.39-46
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• 2017

Background: We evaluated new patient's satisfactory consultation time (SCT) and their willingness to pay additional costs (WPAC) for their SCT. Methods: We surveyed medical service satisfaction, SCT, WPAC for their SCT, and payable amount to 612 new patients of single general hospital and measured their real consultation time (RCT). To compare WPAC and payable amount, we divided RCT into 4 groups (${\leq}3$ minutes, 3-5 minutes, 5-10 minutes, and > 10 minutes), and SCT into 3 groups (${\leq}5$ minutes, 5-10 minutes, and > 10 minutes). On the basis of WPAC, we estimated new patient's SCT. Results: RCT was 6.2 minutes, SCT was 8.9 minutes, and medical service satisfaction score was 4.3 (out of 5). The number of patients having WPAC (payable group) was 381 (62.3%) and the amount was 5,853 Korean won. Their RCT and SCT were longer than non-payable group (6.4 minutes vs. 5.7 minutes, 9.3 minutes vs. 8.2 minutes). From multiple logistic regression analysis, WPAC of RCT 5-10 minutes was higher than that RCT ${\leq}3$ minutes (odds ratio= 1.78). Payable amount was highest in RCT > 10 minutes (6,950 Korea won) and SCT > 10 minutes (7,458 Korean won). Intuitively we suggest 10 minutes as SCT, based on payable group's SCT (9.3 minutes) and cut-off time differentiating payable group with non-payable group (10 minutes). Conclusion: We found that new patient had WPAC for their SCT and the longer the SCT, the greater the amount. From this, we hope that current simplified new patient consultation fee calculating system should be modified combining the consultation time factor.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.3
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• pp.173-184
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• 2013

A multi-level design optimization framework for aerodynamic design of rotary wing such as propeller and helicopter rotor blades is presented in this study. Strategy of the proposed framework is to enhance aerodynamic performance by sequentially applying the planform and sectional design optimization. In the first level of a planform design, we used a genetic algorithm and blade element momentum theory (BEMT) based on two-dimensional aerodynamic database to find optimal planform variables. After an initial planform design, local flow conditions of blade sections are analyzed using high-fidelity CFD methods. During the next level, a sectional design optimization is conducted using two dimensional Navier-Stokes analysis and a gradient based optimization algorithm. When optimal airfoil shape is determined at the several spanwise locations, a planform design is performed again. Through this iterative design process, not only an optimal flow condition but also an optimal shape of an EAV propeller blade is obtained. To validate the optimized propeller-blade design, it is tested in wind-tunnel facility with different flow conditions. An efficiency, which is slightly less than the expected improvement of 7% predicted by our proposed design framework but is still satisfactory to enhance the aerodynamic performance of EAV system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.5
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• pp.635-643
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• 2018

This paper propose a method to identify the motor parameters and improve input voltage error which affect the low speed position error of the back-emf(back electromotive force) based sensorless algorithm and to secure the operation reliability and stability even in the case where the load fluctuation is severe and the start and low speed operation frequently occurs. In the model-based observer used in this paper, stator resistance, inductance, and input voltage are particularly influential factors on low speed performance. Stator resistance can cause resistance value fluctuation which may occur in mass production process, and fluctuation of resistance value due to heat generated during operation. The inductance is influenced by the fluctuation due to the manufacturing dispersion and at a low speed where the change of the current is severe. In order to find stator resistance and inductance which have different initial values and fluctuate during operation and have a large influence on sensorless performance at low speed, they are commonly measured through 2-point calculation method by 2-step align current injection. The effect of voltage error is minimized by offsetting the voltage error. In addition, when the command voltage is used, it is difficult to estimate the back-emf due to the relatively large distortion voltage due to the dead time and the voltage drop of the power device. In this paper, we propose a simple circuit and method to detect the voltage by measuring the PWM(Pulse Width Modulation) pulse width and compensate the voltage drop of the power device with the table, thereby minimizing the position error due to the exact estimation of the back-emf at low speed. The suitability of the proposed algorithm is verified through experiment.

• Journal of Intelligence and Information Systems
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• v.15 no.1
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• pp.51-64
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• 2009

A location tracking sensor such as GPS, INS, Radar, and optical equipments is used in tracking Maneuvering Targets with a multi-sensor, and such systems are used to track, detect, and control UAV, guided missile, and spaceship. Until now, Most of the studies related to tracking Maneuvering Targets are on fusing multiple Radars, or adding a supplementary sensor to INS and GPS. However, A study is required to change the degree of application in fusions since the system property and error property are different from sensors. In this paper, we perform the error analysis of the sensor properties by adding a ground radar to GPS and INS for improving the tracking performance by multi-sensor fusion, and suggest the tracking algorithm that improves the precision and stability by changing the sensor probability of each sensor according to the error. For evaluation, we extract the altitude values in a simulation for the trajectory of UAV and apply the suggested algorithm to carry out the performance analysis. In this study, we change the weight of the evaluated values according to the degree of error between the navigation information of each sensor to improve the precision of navigation information, and made it possible to have a strong tracking which is not affected by external purposed environmental change and disturbance.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.4
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• pp.421-428
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• 2006

Systematic improvement of the environmental performance of industrial products is a core element of good business. Improving the overall environmental performance of products is envisaged as one of the most important strategic goals and objectives in many company policies. This paper demonstrates an Ecodesign approach to develop a product in a systematical way. The objective of this research is two-folds-describing a systematic procedure of implementing Ecodesign in a company and giving a real case example to demonstrate the application of the proposed Ecodesign methodology. The methodology was based on Wimmer et al and consists of seven steps out of the twelve steps for integrating significant environmental aspects of a product and environmental issues resulting from the stakeholder requirements into product design and development. Together with the Ecodesign team of a major domestic car manufacturer the Ecodesign of a car fuel tank unit has been chosen for the case study presented in the paper. The application of the proposed methodology to the fuel tank unit of a car indicates that practical target specifications of the fuel tank unit were derived systematically. This indicates that the seven steps approach can be a viable Ecodesign method for manufacturers to integrate environmental aspects of their products into their product design and development processes.

• Archives of design research
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• v.19 no.5 s.67
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• pp.5-16
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• 2006

The purpose of this research is to bring to the center of focus, the ad creativity, which in turn can generate the highest advertising effects. The study excludes external factors such as personal relationships, academic network and lobbying powers which were prevalent in the Korean situation. A transformational leader can influence charisma, inspiration, intellectual stimulation, individual consideration and performance goal. As the result of this study shows, the core competence that a C.D. may always want to possess at present as well as in the future is to "motivate inspiration". Charisma may be an ability currently in need but this may not necessarily be so in the future. It may be predicted that a softer quality, which is knowledge-based, that provides intellectual stimulation may be a more valued characteristic. It has been suggested that in the increasingly diversifying society of the future, charisma may be a barrier to enhancing creativity. In times of uncertainty and ambiguity, innovative ideas bring economic rewards (Cockayne, 2004). There may be conflicts of views and opinions between individuals and organizations. Turning these into positive outcome to produce innovative ideas, may be an area of further study. However, there must have been studies where informal networking has produced innovative ideas. Therefore, a transformational leader of an organization needs to investigate the dynamics of informal networking within his team.

• Quality Improvement in Health Care
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• v.5 no.2
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• pp.224-237
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• 1998

Background : This is an investigative study to analyse the importance of works perceived by Quality Improvement(QI) Coordinators and to evaluate their current work performances using the questionnaires developed by the investigator. Methods : The data were collected from 37 subjects over two weeks period from Oct. 1 to Oct. 17, 1998 and analysed by the descriptive statistics of SPSS program. The items of questionnaire are consisted of 13 work domains including 73 activities based on Quality Management(QM) Coordinator's job description of National Association for Healthcare Quality:data collection & analysis, communication, monitoring, evaluation, accreditation, tool development, policy development, program development, self development, education & trainning, system design, planning, and consultation & support. Results : 1) Of the performances in 13 work domains, the frequencies of the work performed were accreditation(89%), planning(88%), communication(83%), data collection & analysis(82%), monitoring(76%), policy development(72%), consultation & support (71%), education & trainning(70%), self development(68%), evaluation(63%), tool development(61%), program development(44%) and system design(43%) in order. 2) For the importances (1=not important, 5=very important), the policy development(4.46) scored highest then monitoring(4.42), planning(4.41), education & trainning(4.38), communication(4.35), evaluation(4.34) tool development (4.30), data collection & analysis(4.29), program development(4.22), consultation & support(4.22), accreditation(4.15), self development(4.05) and system design(3.98) in order. 3) There was a difference between the work performance and the perceived importance. The results showed the low performances in policy development, monitoring, education & trainning and evaluation which ranked high by the perceived importance and the high performances in accreditation, data collection & analysis, self development, communication and consultation & support which ranked middle to low by the perceived importance. 4) The reasons for low performances of QI Coordinators were the lack of clear assignment for the responsibility and allowed authority for work to QI Coordinators(30.8%), insufficient member of QI Coordinators(13.9%), lack of hospital director's interest(11.5%), low motivation of QI Coordinators (10.6%) and insufficient knowledge & experience of QI Coordinators (8.8%). Conclusion : Most works were perceived important by QI Coordinators, but there was a difference in the work performance. The works performed over 70% were related with accreditation, data collection & analysis, communication, planning and monitoring, on the other hand under 50% in performances were related with system design, program development, tool development and evaluation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.2
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• pp.161-172
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• 2014

An earth pressure balanced shield TBM with the diameter of 4.4 m was designed and manufactured for a subsea discharge tunnel excavation. Its cutterhead was designed to be optimized for the strongest rock mass condition in the tunnel alignment, and then the applicability of the refurbished shield TBM was validated for its maximum capacity. Especially, the maximum cutter penetration depth for the strongest rock mass condition should be kept to be below 7 mm/rev in order to satisfy the allowable capacities of the shield TBM. From the analysis of TBM advance data, approximately 95% of field data showed the cutter penetration depth below 7 mm/rev. In addition, it was certified that the acting forces of every disc cutter, TBM thrust and torque during TBM driving were within the allowable capacities of the shield TBM and its disc cutters. When real acting forces of the disc cutters in the field were compared with those predicted by the CSM model, they showed the close relationships with each other even though the predictions by the CSM model were approximately 22~25% higher than field data.

• Quality Improvement in Health Care
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• v.8 no.1
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• pp.44-55
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• 2001

Background : This study aimed at identifying the effect of the standardized protocol on lowering the incidence of the ventilator associated pneumonia(VAP). Methods : The standard protocol focusing on decreasing VAP was made and applied at 5 ICUs (Medical ICU, surgical ICU, Respiratory ICU, Neonatal ICU, Pediatric ICU) in a university affiliated tertiary hospital, from April 1, 2000 to Oct 31, 2000. The protocol involved 3 parts : hand washing, the suctioning method and ventilator circuit management. All the nursing personnel received intensive education which was consisted of lecture, video film and demonstration. 176 nurses reported the performance of handwashing pre and post intervention. And randomly selected 15 nurses were observed by charge nurse and the handwashing practice was analyzed pre and post intervention. The incidence of VAP was compared with the former year incidence. Results : The self reported frequency of hand washing increased. In the direct observation of handwashing, the frequency, time, thoroughness of hand washing during 8 hours day duty was found to be improved. The frequency was increased from 1.1 time to 4.1 times; the time was improved from 1.7 seconds to 5.7 seconds and the thoroughness of the washing practice was from 0.2 times to 3.0 times respectively (p<0.001). The incidence of VAP decreased from at a rate of 15.63 number of case per 1,000 ventilator-day (April 1~August 31, 1999) to 7.23 number of case per 1,000 ventilator-days(April 1~Oct 31, 2000)(P<0.001). Conclusion : We developed the protocols which included hand washing, the suctioning method, and ventilator circuit management. Through the implementation of the protocol, the performance of hand washing improved and the VAP incidence rate in ICU was decreased.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.4
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• pp.351-361
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• 2014

Compared to a terrestrial communication, the high BER(Bit Error Ratio) and low channel bandwidth are the major factor of throughput degradation due to characteristics of underwater channel. Therefore, a MAC protocol must be designed to solve this problem in UWASNs(Underwater Acoustic Sensor Networks). MAC protocols for UWASNs can be classified into two major types according to the contention scheme(Contention-free scheme and Contention-based scheme). In large scale of sensor networks, a Contention-based scheme is commonly used due to time-synchronize problem of Contention-free scheme. In the contention-based scheme, Each node contends with neighbor nodes to access network channel by using Back-off algorithm. But a Slot-Time of Back-off algorithm has long delay times which are cause of decrease network throughput. In this paper, we propose a new scheme to solve this problem. The proposed scheme uses variable Slot-Time instead of fixed Slot-Time. Each node measures propagation delay from neighbors which are used by Slot-time. Therefore, Slot-Times of each node are optimized by considering node deployment. Consequently, the wasted-time for Back-off is reduced and network throughput is improved. A new mac protocol performance in throughput and delay is assessed through NS3 and compared with existing MAC protocol(MACA-U). Finally, it was proved that the MAC protocol using the proposed scheme has better performance than existing MAC protocol as a result of comparison.