• Proceedings of the Korean Reliability Society Conference
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• 2000.11a
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• pp.387-395
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• 2000

Circular consecutive-k-out-of-n:F system when the failure of component is dependent is studied. We assume that the failure of a component in the system increase the failure rate of the survivor which is working just before the failed component. In this case, a mean time to failure (MTTF), a average failure number of the system, and the expected cost per unit time are obtained. Then the minimum number of consecutive failed components to cause system failure to minimize the expected cost per unit time is determined as searching paths to system failure. And various numerical examples are studied.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.4
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• pp.79-85
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• 2002

In general, estimates of average service lives and of mortality functions are less well-based than most types of economic statistics published by statistical offices. Therefore, hypotheses about service lives of tangible assets and their distribution are most difficult aspects to tackle. In this paper, estimates of service lives based on directly observed data on domestic industrial property and retirement rates are presented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.557-559
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• 2012

The fire distress detection and rescue user terminal, which rescue the survivor by using the direction finding of distress place and sensing techniques, was design and implemented. The user terminal provides the rescue function in the place of evil surroundings that can not be available the communication facilities. The rescue user terminal provides the portable configuration, which consists of a RF board with radio frequency of 2.45 GHz and inner antenna, and a control board. The inner antenna with $60^{\circ}$ or $120^{\circ}$ directivity, which use the triangulation, detects the rescue signal from survivor. The rescue was managed by allotment of user ID and can use the bidirectional audio channel using radio frequency of 5.8 GHz.

• The Journal of the Korea Contents Association
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• v.14 no.7
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• pp.356-366
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• 2014

The purpose of this study was to identify the impact of the mood state on the quality of life (QOL) of the female breast cancer survivor. The study was cross-sectional survey. This study was conducted from September 10th to September 20th, 2013. The subjects were 120 breast cancer survivors in Seoul city in Korea. The obtained data were analyzed by SPSS/WIN 21.0 program. The mean score of mood state was 39.20 and the mean score of the quality of life was 83.59. The levels of mood state and the quality of life were negatively correlated. The significant factors influencing quality of life were vigor and anger of the mood state, religion that explained 39.1% of the variance. The results suggests that appropriate support service should be provided to improve the quality of life after nurses evaluate breast cancer survivor's mood states and identify the symptoms of mood disturbances.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6C
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• pp.487-497
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• 2008

This paper proposes a new adaptive QRD-M algorithm for MIMO systems. The proposed scheme controls the number of survivor paths,0 based on the channel condition at each layer. The original QRD-M algorithm used fixed M at each layer and it needs large M to achieve near-MLD (maximum-likelihood detection) performance. However, using the large M increases the computation complexity. In this paper, we further effectively control M by employing the channel indicator which includes not only the channel gain, but also instantaneous noise information without necessity of SNR measurement. We found that the ratio of the minimum path metric to the second minimum is good reliability indicator for the channel condition. By adaptively changing M based on this ratio, the proposed scheme effectively achieves near MLD performance and computation complexity of the proposed scheme is significantly smaller than the conventional QRD-M algorithms.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.12 s.354
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• pp.1-8
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• 2006

In this paper, we propose carrier phase synchronization algorithm which are base on turbo coded system for DVB-RCS. There have been two categories of phase estimator, single estimator outside turbo code decoder and multiple estimators inside turbo code decoder. In single estimator, we use the estimation algorithm that ML(Maximum Likelihood) and LMS(Least Mean Square), also three different soft decision methods are proposed. Multiple estimator apply PSP(Per Survivor Processing) algorithm additionally. We compared performance between single estimator and Multiple estimator in AWGN channel. We presented the two methods of PSP algorithm for performance elevation. First is the Bi-directional channel estimation and second is binding method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11A
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• pp.862-869
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• 2009

We propose a new adaptive K-best Sphere Decoding (SD) algorithm for Multiple Input Multiple Output (MIMO) systems where the number of survivor paths, K is changed based on the characteristics of path metrics which contain the instantaneous channel condition. In order to overcome a major drawback of Maximum Likelihood Detection (MLD) which exponentially increases the computational complexity with the number of transmit antennas, the conventional adaptive K-best SD algorithms which achieve near to MLD performance have been proposed. However, they still have redundant computation complexity since they only employ the channel fading gain as a channel condition indicator without instantaneous Signal to Noise Ratio (SNR) information. hi order to complement this drawback, the proposed algorithm use the characteristics of path metrics as a simple channel indicator. It is found that the ratio of the minimum path metric to the other path metrics reflects SNR information as well as channel fading gain. By adaptively changing K based on this ratio, the proposed algorithm more effectively reduce the computation complexity compared to the conventional K-best algorithms which achieve same performance.

• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.97-103
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• 2012

A very low complexity QRD-M algorithm based on limited search area is proposed for MIMO systems. The conventional QRD-M algorithm calculates Euclidean distance between all constellation symbols and the temporary detection symbol at each layer. We found that performance will not be degraded even if we adaptively restrict the search area of the candidate symbols only to the neighboring points of temporary detection symbol according to the channel condition at each layer. As a channel condition indicator, we employ the channel gain ratio among the layers without necessity of SNR estimation. The simulation results show that the proposed scheme effectively achieves near optimal performance while maintaining the overall average computation complexity much smaller than the conventional QRD-M algorithm.

• The Korean Journal of Emergency Medical Services
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• v.9 no.1
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• pp.79-87
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• 2005

Purpose: Investigates the results of CPR operation in visited patients with arrest state, and element to affect the results, and it is checks a problem, and it is made to promote. Methods: As for this study, analysis studied the results that operation CPR with the object arrest patients of 69 visited Jecheon Seoul hospital emergency center for during the period from January 2002 to February 2005. It was played writing partly changed In-hospital Utstein Style, and to stick a record in it. Paramedic which participated in CPR directly did the record of a variable, As for the data processing, use SPSS Version 12.0 for Windows. Results: It was male 68.1% female 31.9% for 69 people, and the sex ratio didn't affect return of spontaneous circulation, with female 8 people to male 16 people for ROSC(Return of spontaneous circulation) 24 people. with female 14 people to male 31 people for NROSC(Non-return of spontaneous circulation) 45 people(p>0.05). The initial EKG rhythm was asystole 34.8%, VF 31.9%, The case that initial EKG was VF compared it to a patient of asystole, and a survivor had a lot of VF and there were a lot of survivors(p<0.05). The wasn't relativity between VF and PEA(p>0.05), The CPR lead time was short in ROSC with NROSC $25.0{\pm}15.0$ minutes, ROSC $11.9{\pm}10.7$ minutes(p<0.01). Epinephrine administer time was NROSC $3.0{\pm}4.1$ minutes, ROSC $2.1{\pm}1.9$ minutes(p>0.05). It was survivor 18 people(21.1%) than 24 hours and the PAM Index affected in ROSC. with $9.0{\pm}1.2$ points NROSC, with $1.6{\pm}1.7$ points ROSC(p<0.01). A correlation was high between a CPR lead time and PAM Index(p<0.02), a correlation was examined by being high between ROSC and a CPR lead time, PAM Index(p<0.01).

• Journal of Chest Surgery
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• v.54 no.1
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• pp.36-44
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• 2021

Background: Extracorporeal membrane oxygenation (ECMO) has become increasingly accepted as a life-saving procedure for patients with severe acute respiratory distress syndrome (ARDS). This study investigated the relationship between cumulative fluid balance (CFB) and outcomes in adult ARDS patients treated with ECMO. Methods: We retrospectively analyzed the data of adult ARDS patients who received ECMO between December 2009 and December 2019 at Korea University Anam Hospital. CFB was calculated during the first 7 days after ECMO initiation. The primary endpoint was 28-day mortality. Results: The 74 patients were divided into survivor (n=33) and non-survivor (n=41) groups based on 28-day survival. Non-survivors showed a significantly higher CFB at 1-7 days (p<0.05). Cox multivariable proportional hazard regression revealed a relationship between CFB on day 3 and 28-day mortality (hazard ratio, 3.366; 95% confidence interval, 1.528-7.417; p=0.003). Conclusion: In adult ARDS patients treated with ECMO, a higher positive CFB on day 3 was associated with increased 28-day mortality. Based on our findings, we suggest a restrictive fluid strategy in ARDS patients treated with ECMO. CFB may be a useful predictor of survival in ARDS patients treated with ECMO.