• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.131.6-131
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• 2001

During the operation of crane system in container yard, it is necessary to control the crane trolley position and loop length so that the swing of the hanging container is minimized. Recently an automatic control system with high speed and rapid transportation is required. Therefore, we designed a controller to control the stacking crane system.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.417-424
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• 2003

In this paper, we introduce and analyze a feedback control model of TCP/AQM dynamics. Then, we propose the Pro-active Queue Management (PAQM) mechanism, which can provide proactive congestion avoidance and control using an adaptive congestion indicator and a control function for wide range of traffic environments. The PAQM stabilizes the queue length around a desired level while giving smooth and low packet loss rates independent of the traffic load level under a wide range of traffic environment. The PAQM outperforms other AQM algorithms such as Random Early Detection (RED) [1] and PI-controller [2]

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.647-648
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• 2006

In this paper, magnetic levitation characteristics of hybrid magnets are experimentally shown under the newly proposed airgap condition. The digital PID controller is utilized to control the airgap of the magnetic levitation system.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.34.5-34
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• 2001

This paper presents a reliable H$\infty$ controller design for singularly perturbed systems by the delta operator approach that guarantees stability with a known H$\infty$ norm bound in case of failures in some control channels. Prespecified are the control channels that may experience failures. Sensor outage is covered in this paper It is shown that the delta systems have improved finite wort length characteristics in the example.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.2
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• pp.37-45
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• 2016

Control chart is representative tools of statistical process control (SPC). It is a graph that plotting the characteristic values from the process. It has two steps (or Phase). First step is a procedure for finding a process parameters. It is called Phase I. This step is to find the process parameters by using data obtained from in-controlled process. It is a step that the standard value was not determined. Another step is monitoring process by already known process parameters from Phase I. It is called Phase II. These control chart is the process quality characteristic value for management, which is plotted dot whether the existence within the control limit or not. But, this is not given information about the economic loss that occurs when a product characteristic value does not match the target value. In order to meet the customer needs, company not only consider stability of the process variation but also produce the product that is meet the target value. Taguchi's quadratic loss function is include information about economic loss that occurred by the mismatch the target value. However, Taguchi's quadratic loss function is very simple quadratic curve. It is difficult to realistically reflect the increased amount of loss that due to a deviation from the target value. Also, it can be well explained by only on condition that the normal process. Spiring proposed an alternative loss function that called reflected normal loss function (RNLF). In this paper, we design a new control chart for overcome these disadvantage by using the Spiring's RNLF. And we demonstrate effectiveness of new control chart by comparing its average run length (ARL) with ${\bar{x}}-R$ control chart and expected loss control chart (ELCC).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.12
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• pp.35-40
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• 2006

The combustion instability in a model dump combustor with an exhaust nozzle and the possibility of combustion control using a loudspeaker to these instabilities were studied. By changing inlet velocity, combustor length and equivalence ratio, dynamic pressure signals and flame structures were simultaneously taken. Because inlet velocity and combustor length affect the life time of vortex in the dump combustor, the results showed that as the combustor length increased and the inlet velocity decreased, the instability frequency decreased and the maximum power spectral density of the dynamic pressure generally decreased. Also, instability frequency and maximum power spectral density of the dynamic pressure increased with the increment of equivalence ratio. From the data of close-loop control, the optimum time-delay control using a loudspeaker was confirmed to be able to reduce the vortex shedding induced from the mixed acoustic-convective mode combustion instability.

• Journal of Embryo Transfer
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• v.25 no.1
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• pp.21-27
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• 2010

The increase in the total number of cows on farms, which breed Korean Native Cattle (KNC), is associated with many problems. In particular, the services per conception and calving interval have increased. In this study, we examined the effect of dietary supplementation with vitamin and mineral complex on the estrus rate, pregnancy rate, gestation length, and birth weight of KNC calves. Multiparous or primiparous KNC were divided into 3 groups with 40 heads per group. Experimental group 1 was administered a consisting of 35,000 IU vitamin A, 100 IU vitamin E, 200 mg $\beta$-carotene, 200 mg Zn methionine, and 1.5 mg Se. Experimental group 2 was administered a vitamin complex (100 g/day) consisting of 100 IU vitamin E and 200 mg $\beta$-carotene. In the case of multiparous KNC, the estrus detection rate in the control group was 90.0% and those in the experimental groups were 75.0% to 95.0%. However, the first-service pregnancy rate after parturition in the control group was 41.2%, which was significantly lower than that in the experimental groups (71.0% to 76.7%; p<0.05). The average duration of pregnancy in the group supplemented with the vitamin complex was days, which was similar to that in the case of the control group. The birth weight of calves from cows fed with vitamin complex was 25.3 to 27.0 kg, which was similar to that in the case of the control group (25.2 to 26.0 kg). In the case of primiparous KNC, no differences in the estrus rate, pregnancy rate, gestation length, or the birth weight of calves were noted between the groups. Thus, dietary supplementation vitamin and mineral complex have no effect on the reproductive efficiency in primiparous cows, but the pregnancy rate was observed to have increased in multiparous KNC with these supplements.

• Archives of Plastic Surgery
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• v.32 no.4
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• pp.521-528
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• 2005

The purpose of this research is to find out the degree of cartilage regeneration by inserting the atelo-collagen scaffold obtained from dermis of a calf on cartilage defect site. Dissection underneath the perichondrium by the periosteal elevator on both side of ears of six New Zealand white rabbits were made to expose the cartilage, leaving pairs of circular holes 3, 6, 9 mm width with punches. One hole was left for a control, and on the other hole atelo-collagen scaffold of the same size was transplanted. In postoperative 1, 2, 4 weeks, the tissues were dyed. The length of long axis of neocartilage was measured through an optical microscope with a 0.1 mm graduation at original magnification, ${\times}40$. In the first and second week, both group showed no sign of cartilage regeneration. In the fourth week, regeneration on marginal portions was observed on all groups and the average values of length of long axis of neocartilage according to defect size were as follows: In the cases with 3mm defect, it was $0.85{\pm}0.30mm$ in the control group, and $1.85{\pm}0.38mm$ in the graft group; in the cases with 6 mm defect, $1.33{\pm}0.58mm$ in the control group, and $2.25{\pm}0.46mm$ in the graft group; and in the cases with 9 mm defect, $2.33{\pm}0.77mm$ in the control group, and $4.47{\pm}1.39mm$ in the graft group. This means that the collagen scaffold has an influence on the regeneration of neocartilage. But the relative ratio of the length of neocartilage to cartilage defect size was not significant in the statistics.

• Quality Improvement in Health Care
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• v.10 no.2
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• pp.154-163
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• 2003

Purpose: The aim of this study is to develop and apply the critical pathway to the nasal bone fracture patients and to elucidate its effect. Methods: Critical pathway (CP) sheet and questionnaire were developed by a team approach. Critical pathway were applied to 30 nasal bone fracture patients (CP group) from June 2001 to November 2001. Length of hospitalization, cost for hospitalization and bed turnover rate of CP group were compared to those of the 30 patients who had same disease entities and treated by conventional regimen (control group). Results: Length of hospitalization in the CP group (4.20 day) were significantly shorter than that of control group (6.21 day). Mean cost for hospitalization of the CP group (492,106 won) were significantly lower than that of control group (678,376 won). Bed turnover rate in CP group (2.5) were higher than that of control group. The patients satisfaction for the medical personnel, explanation regarding operation procedure, therapeutic operation fee, and length of hospitalization were all affirmative. Conclusion: Critical pathway that we developed for nasal bone fracture definitely improved the quality of treatment and lowered cost of medical service. Furthermore, other critical pathways should be developed for another facial trauma patients.

• Quality Improvement in Health Care
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• v.18 no.1
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• pp.37-55
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• 2012

Objectives : This study was conducted to evaluate the effect of fixed critical pathway with emr (electronic medical record) on the length of hospital stay, the cost and quality of care provided to gastrectomy patients in a university hospital and to develop flexible critical pathway with emr which can be used excluded or drop-out patients. Methods : Thirty-eight patients with gastrectomy were included as case group and Thirty-four patients included as control group. The comparison between control and case with using fixed critical pathway were done. To develop and to evaluate usefulness of flexible critical pathway with flexible data base, simulation was done for flexible critical pathway with drop-out patients. Result : The major results of this study were as follows: There were no significant differences in patient clinical conditions and no sign of deterioration of quality from critical pathway. The length of hospital stay was 11 days in control group, 8 days in path group(P<0.01). The total costs during the hospital stay were reduced in path group. However the cost per day was significantly increased from reduction of hospital stay(554,352 won in control, 645,669 won in path group). One hundred percentage of drop out patients(60) in the simulation of flexible critical pathway was successful. Conclusion : Computerized critical pathway reduced the length of hospital stay, total hospital costs and resource utilization without harming quality of patient care. The flexible critical pathway program can be used as one of the powerful management tools for reducing the practice variations and increasing the efficiency of care process and decreasing the workload of doctors and nurses in Korean hospital settings.