• Progress in Medical Physics
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• v.4 no.1
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• pp.23-28
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• 1993

Radiation physics quality programs operate in a data rich enviranment. In quality control/quality assurance of treatment planning systems, quality indicators include isodose planning system, isodose calculation system, data set and equipment.

• Korean Journal of Construction Engineering and Management
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• v.1 no.2 s.2
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• pp.53-62
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• 2000

A concrete element is obtained through multi-steps, and its quality is affected by site conditions and control constituents of procedures. In these regards, in order to assure designed qualities of concrete and associated materials of the element good quality control method is necessary in various procedures. The existing quality control measures do not satisfy the requirements for the quality control activities at each production step. This study provides a more effective checklist for each phase of concrete work, which improves existing quality control checklist through extensive research on current practices and surveys from expertises. This paper also proposes the application of multi-facet codes to develop a customized checklist to improve the efficiency in field practices and the effectiveness in assuring the designed performance of concrete. This study finally provides a more effective checklist for each phase of concrete work by improving usability of the developed project sensitive matric quality control checklist through application experiments on construction project sites.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.877-881
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• 2014

Objective: To evaluate risk factors for gallstones after gastrectomy. Methods: To identify documents published from 1990 to 2011 the Pubmed, Cochrane Library, Springer Link, CBM and WanFang databases were searched and a meta-analysis was performed with RevMan 5.2 software for odds ratios and 95%CIs. Results: Fifteen studies were selected for the meta-analysis. The pooled ORs [95%CIs] were 0.56 [0.43, 0.73], (P<0.0001) for digestive tract reconstruction, 0.80 [0.54, 1.17], (P=0.25) for pylorus preservation, 0.33[0.15, 0.75], (P=0.008) for resection scope of stomach, 0.33 [0.15, 0.75], (P=0.008) for lymphadenectomy, and 0.13 [0.05, 0.33], (P<0.0001) for vagotomy. Conclusions: Digestive tract physical reconstruction and vagus nerve preservation can reduce the morbidity of gallstones after gastrectomy. Total gastrectomy can add to the morbidity of galltones as does increasing the degree of lymph node dissection. There was no significant difference in gallstones with or without pylorus preservation.

• The Korean Journal of Health Service Management
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• v.7 no.1
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• pp.21-34
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• 2013

Hospitals in Korea are enforcing a quality control over 119Emergency Medical Services to increase the survival rate of Out of Hospital Cardiac arrest patients. This study is to analyze the factors that effect the survival rate of Out of hospital Cardiac arrest patients by comparing the results of before and after the quality control enforcement. Cardiac arrest patients can be assorted into pre-decision group and decision group. The study analyzed the survival factors which was based on the adequate use of 119 BLS and ACLS usage rates, response time of 119EMS, qualification of ambulance worker, number of EMS team members, and adequate use of AED according to ECG diagnosis. The analyzation was done over total 1,233 of Cardiac arrest patients from January 1, 2010 to December 31, 2011 After the enforcement of the quality control, the usage of Vital sign check and BLS showed a big difference. Especially, as the usage of ECG showed a significant difference, Shockable rhythm, which is the most important to Cardiac arrest patients, also showed a significant difference. After the enforcement of quality control, the performance of ACLS showed a significant difference in IV. The study showed 119 ambulance workers provided better service in Vital sign and BLS and ACLS after the enforcement of quality control. It is considered a 119 ambulance service effects the survival rate of Cardiac arrest patients. Therefore, it can increase the survival rate and it is necessary to continue a quality control.

• International Journal of Control, Automation, and Systems
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• v.6 no.4
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• pp.596-606
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• 2008

In this paper, we present a co-design methodology of dynamic optimal network-bandwidth allocation (ONBA) and adaptive control for networked control systems (NCSs) to optimize overall control performance and reduce total network-bandwidth usage. The proposed dynamic co-design strategy integrates adaptive feedback control with real-time scheduling. As part of this co-design methodology, a "closed-loop" ONBA algorithm for NCSs with communication constraints is presented. Network-bandwidth is dynamically assigned to each control loop according to the quality of performance (QoP) information of each control loop. As another part of the co-design methodology, a network quality of service (QoS)-adaptive control design approach is also presented. The idea is based on calculating new control values with reference to the network QoS parameters such as time delays and packet losses measured online. Simulation results show that this co-design approach significantly improves overall control performance and utilizes less bandwidth compared to static strategies.

• The Korean Journal of Nuclear Medicine Technology
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• v.21 no.1
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• pp.60-64
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• 2017

Purpose Westgard multi-rules application based on test quality improvement and commercialized international standard has been widely used in quality control. However, it is difficult to applicate the Westgard multi-rules in nuclear medicine in vitro tests due to the larger sample sizes and the simultaneous measurement of quality control material and patient sample. This study investigated the usefulness of Westgard multi-rules application in nuclear medicine in vitro tests. Materials and Methods A total of 282 systematic error multi-rules (22s, 101s) recorded in the samsung medical center computer system from January 2013 to June 2016 along with 117 cases of corrective measure record was analyzed. The Quality control implementation is recorded in Hospital information system were divided into 4 high-level areas including quality control material error, experimental procedural error, Kit lot number management error, and others. To prevent quality control material error, the existing method that each staff used their own method was changed. The staff who in charge of managing the quality control material was designated and daily consumption amount of every test was strictly controlled by one person. To prevent other errors, every test step was standardized so that the entire test procedures are identically implemented. Results The total quality control implementation was 117 cases; As a result, 62 quality control material errors were 62 cases, experimental process errors were 24 cases, Kit lot number control errors were 18 cases, and other errors were 13 cases. The quality control material error was corrected and could be used fresh materials within 2 days after thawing. The cases of systemic error were decreased to causes as quality control material error. The quality control materials were reduced above 10 vials to a monthly average. In addition, these errors of experimental processing and Kit lot number were improved by test standardization. Consequently, the cases of 101s and 22s in systematic error rules decreased at least 2 cases to a monthly average. Conclusion To confirm of systematic error through multi-rules application quickly, it is necessary to base on management of the QC material, target values and standard deviation. Moreover, in the event of a systematic error, it was found important to record measures based on test cause analysis. The experiment results are expected to contribute to internal quality control improvement and prompt and accurate result reporting through error recording and causal analysis based on Westgard multi-rules analysis.

• Proceedings of the Korean Society for Quality Management Conference
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• 1998.11a
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• pp.217-224
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• 1998

A cost model, controlling multiple dependent subprocesses with minimum cost, is derived by renewal theory approach. The optimal multiple cause-selecting control chart and individual Y control chart are thus constructed to monitor the specific product quality and overall product quality contributed by the multiple dependent subprocesses. They may be used to maintain the process with minimum cost and effectively distinguish which component of the subprocesses is out of control. The optimal design parameters of the proposed control charts can be determined by minimizing the cost model using simple grid search method, An example is given to illustrate the application of the optimal multiple cause-selecting control chart and individual Y control chart.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.11
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• pp.1571-1577
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• 2015

A new mixed mode control of constant power and constant current for resistance spot welding inverter is proposed to improve the weld quality. The conventional control scheme adopts constant current or constant power control mode, however, it is not easy to guarantee the high weld quality because of the nonlinear resistance characteristics of the welding point. The proposed method utilizes the nonlinear characteristics by measuring the dynamic resistance in real time. Therefore, it is possible for the welder to be controlled adaptively depending on the welding state. Experimental results show that the proposed control scheme improves the weld quality by 6.8 times compared with the conventional constant current mode control.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.860-869
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• 2011

It is very important that reduce the maintenance cost and extend life time of the urban transit EMU through effective maintenance method research. The maintenance cost of the urban transit EMU shares 60%~70% of it's life cycle cost. It means that the maintenance cost is bigger than the introduction cost of the urban transit EMU. In this study, I introduces a quality control technique to improve the urban transit vehicle reliability. I suggest the control chart using quality control technique. And the control charts apply to the Static Inverter of EMU.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.9
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• pp.84-90
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• 1997

We proposed a new bit-rate control algorithm to improve MPEG-2 video software encoder. Bit-rate Control plays an improtant role in picture quality of MPEG-2 encoder. To achieve better encoding performance such as controlling picture quality and using bity properly, we proposed a MPEG-2 bit-rate control algorithm using linear average Step-Size. Using a benchmark Program, we compared our algorithm with MPEG-2 Test Model 5. Our proposed algorithm showed better Bit-Rate Control with respect to used bits, picture quality.