• Communications for Statistical Applications and Methods
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• 제19권2호
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• pp.219-224
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• 2012

This article considers the mean time to failure(MTTF) of a dependent parallel system. We study how the degree of dependency components influences the increase in the mean lifetime for this system. The results are illustrated by tables and figures.

• 통합자연과학논문집
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• 제7권1호
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• pp.67-73
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• 2014

We consider the mean value function for NHPP software reliability model and time series regression model in software failure data. We estimate parameters for the proposed models from two data sets. The values of SSE and MSE is presented from two data sets. We compare the predicted number of faults with the actual two data sets using the mean value function and regression curve.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1379-1382
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• 1997

We introduce a fast implementation of the adaptive transversal filter which uses least-mean-square(LMS) algorithm. The fast Hadamard transform(FHT) is used for the implementation of the filter. By using the proposed filter we can get the significant time reduction in computatioin over the conventional time domain LMS filter at the cost of a little performance. By computer simulation, we show the comparison of the propsed Hadamard-domain filter and the time domain filter in the view of multiplication time, mean-square error and robustness for noise.

• 한국경영과학회지
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• 제13권1호
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• pp.47-47
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• 1988

Rapid globalization of production and marketing functions makes choice of international transportation mode of great importance. In this paper, transportation mode is characterized by two factors, mean and variability of transportation lead time. We developed a simple mathematical model to estimate the relative impact of mean lead time, lead time variance and demand variance on the required average inventory level under specified service rates.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권2호
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• pp.252-259
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• 2017

In this paper, we propose a novel method for extracting an accurate depth of a trap that causes RTS(Random Telegraph Signal) noise. The error rates of the trap depth rely on the mean time constants and its ratio. Here, we determined how many data of the capture and emission time constant are necessary in order to reduce the trap depth error caused by an inaccurate mean time constant. We measured the capture and emission time constants up to 100,000 times in order to ensure that the samples had statistical meaning. As a result, we demonstrated that at least 1,000 samples are necessary to satisfy less than 10% error for trap depth. This result could be used to improve the accuracy of RTS noise analysis.

• Asian Pacific Journal of Cancer Prevention
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• 제17권5호
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• pp.2475-2478
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• 2016

Background: Laparoscopic partial nephrectomy is one of the major surgical techniques for small renal masses. However, it is difficult to manage cutting and suturing procedures within acceptable time periods. To overcome this difficulty, we applied a three-dimensional (3D) video system with laparoscopic partial nephrectomy, and evaluated its utility. Materials and Methods: We retrospectively enrolled 31 patients who underwent laparoscopic partial nephrectomy between November 2009 and June 2014. A conventional two-dimensional (2D) video system was used in 20 patients, and a 3D video system in 11. Patient characteristics and video system type (2D or 3D) were recorded, and correlations with perioperative outcomes were analyzed. Results: Mean age of the patients was $55.8{\pm}12.4$, mean body mass index was $25.7{\pm}3.9kg/m^2$, mean tumor size was $2.0{\pm}0.8cm$, mean R.E.N.A.L nephrometry score was $6.9{\pm}1.9$, and clinical stage was T1a in all patients. There were no significant differences in operative time (p=0.348), pneumoperitoneum time (p=0.322), cutting time (p=0.493), estimated blood loss (p=0.335), and Clavien grade of >II complication rate (p=0.719) between the two groups. However, warm ischemic time was significantly shorter in the 3D group than the 2D group (16.1 min vs. 21.2min, p=0.021), which resulted from short suturing time (9.1 min vs. 15.2 min, p=0.008). No open conversion occurred in either group. Conclusions: A 3D video system allows the shortening of warm ischemic time in laparoscopic partial nephrectomy and thus may be useful in improving the procedure.

• Journal of Korean Neurosurgical Society
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• 제64권1호
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• pp.60-68
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• 2021

Objective : Until recently, the transfemoral approach (TFA) was used as the primary method of arterial approach in acute ischemic stroke (AIS). However, TFA resulted in longer reperfusion times and worse outcomes in the mechanical thrombectomy (MT) of patients with complex aortic arches and significant carotid tortuosity. We found that the transradial approach (TRA) is a more favorable alternative approach for MT in such cases. Methods : We performed a retrospective review of our institutional database to identify 202 patients who underwent MT for AIS between February 2015 and December 2019. Patient characteristics, cause of TFA failure, procedure time, intra-procedural complications, and outcomes were recorded. Results : Eleven (5.4%) of 202 patients, who underwent MT for AIS, crossed over to TRA for recanalization, and eight (72%) of 11 achieved successful recanalization (≥modified Treatment in Cerebral Infarction 2b). The mean age (mean±standard deviation [median]) was 82.3±6.6 (76) years, and five of the 11 patients were male. The last seen normal to puncture time was 467.9±264.72 (264) minutes; baseline National Institutes of Health Stroke Scale score was 28.9±14.5 (16). Six (55%) of the 11 patients had right vertebrobasilar occlusions, and the remaining five (45%) had anterior circulation occlusive disease. The time from groin puncture to final recanalization time (overall procedural time) was 78.0±20.1 (62) minutes. The mean crossover time from TFA to TRA was 45.2±10.5 (41) minutes. The mean time from radial puncture to final recanalization was 33.8±10.5 (28) minutes. Distal thrombus migration events in previously unaffected territories occurred in 3/8 patients (37%). At 90 days, three patients (28%) had a favorable clinical outcome. Conclusion : Although rare, failure of TFA has been known to occur during MT for AIS. Our results demonstrate that TRA may be an alternative option for AIS intervention for select patients with subsequent timely revascularization. However, the incidence of distal thrombus migration was high, and the first puncture to reperfusion time was prolonged because of the time taken for the crossover to TRA after failure of TFA. This study provides some evidence that the TRA may be a viable alternative option to the TFA for MT of AIS.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 추계학술대회 논문집
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• pp.28-33
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• 1992

The paper describes a new mean specific cutting pressure model in order to improve the accuracy of prediction of cutting force for face milling. The new mean specific cutting pressure model produces a mean specific cutting pressure and coefficients applied to existing cutting model not by traditional method but by considering intermittence and variation of chip width according to insert cutting position to take into cutter geometry machining condition and width of workpiece, and considering a mean measure force according to spindle eccentricity and mean measure force according to spindle eccentricity and insert initial position errors.. The simulated forces in X, Y, Z directions resulted from the simulated cutting model and the new cutting model are compared with measured forces in the time end frequency domains. The simulated forces in the time and frequency domains. The simulated forces resulted from the new cutting model have a good degreement with measured forces in comparison with these resulted from the existing cutting model

• Asian-Australasian Journal of Animal Sciences
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• 제19권11호
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• pp.1603-1609
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• 2006

To estimate undegraded intake protein (UIP) fraction in feeds and fodders, on the basis of their neutral detergent insoluble N content was studied. Samples of six feeds and forages were incubated in situ for a time equivalent to their mean retention time, estimated on the basis of their digestibility plus 10 h (to account for a lag in passage of particles from the rumen). The samples were incubated for 0, 25, 50, 75 and 100% of the estimated total mean retention time. UIP value of leguminous forages, obtained from the fractional rates of degradation and passage, were highly correlated with those estimated from samples incubated for 75% of total mean retention time, while incubating the non-leguminous forages and groundnut cake for this point over estimate the UIP fraction.

• 대한조선학회지
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• 제22권2호
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• pp.27-34
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• 1985

In this paper, the second order time mean forces acting on the circular cylinder floating on the free surface of a finite water depth are calculated. Under the assumption that fluid is idea and the wave the linear gravity wave, the velocity potential is calculated by the source distribution method, and the second order time mean lateral and vertical drifting forces are calculated by the direct integration of fluid pressures over the immersed body surface. The comparison of the lateral drifting forces with Rhee's results by momentum theorem shows good agreements. And it is shown that the second order time sinkage forces of a floating circular cylinder cross zero for all water depths.