• The Journal of the Korea Contents Association
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• v.4 no.2
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• pp.50-60
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• 2004

Recently, most of the embedded system is required not only many functions but also real-time characteristics in purpose. In the hard real-time system, especially, strict deadline of periodic task can affect the performance of the system. In this paper, we design and implement the scheduler based on RM(Rate-Monotonic) rule. This scheduler makes feasible patterns based on EDF(Earliest deadline first) rule with extended schedulability inspection before execution, for periodic task-set that has high CPU utilization and then, execute periodic task-set depended on feasible patterns. The feasible pattern formed into EDF rule is capable of the efficiency of CPU up to 100 percentage and by the referenced execution of the feasible pattern is possible of removing the red-time scheduling overhead that is the defect of the order of dynamic assignment rule.

• Journal of the Korean Chemical Society
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• v.39 no.9
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• pp.685-691
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• 1995

EHMACC and EHPC programs written in VAX version to calculate the tight-binding extended Huckel method is converted into the micro-soft fortran available to PC. The band calculation of LaNiO3 unit cell and extended ($2{\times}2{\times}1$) cell with perovskite structure is made by the PC/386 and PC/486. The calculation is also made for the DOS and the COOP. It is supposed that the electronic property of $LaNiO_3$ is semiconductor along to the ${\Gamma}{\rightarrow}H,\;H{\rightarrow}N,\;and\;N{\rightarrow}{\Gamma}(2D)$ direction with band gap about 0u.35 eV, while metal property in ${\Gamma}{\rightarrow}P\;and\;P{\rightarrow}N(3D)$ direction. The oxygen atom property in $LaNiO_3$ is more effectively affected by oxygen atom position than defect of nickel atom.

• Journal of Chest Surgery
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• v.39 no.12 s.269
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• pp.906-912
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• 2006

Background: Ventricular septal defect(VSD) is rare but feared complication after acute myocardial infarction. The patient could survive by surgery only, but the surgical mortality is still high. We investigate the surgical result and predictors for early surgical mortality. Material and Method: Between August 1993 and February 2006, 8 patients (male, 2: female, 6) with postinfarct VSD underwent surgical repair. Seven patients had one-vessel disease of left anterior descending artery, and 6 of them had wide extension of infarction to posterior septal wall as well as anterior septal wall of both ventricles. One patient had concomitant coronary bypass grafting to a coronary lesion unrelated to the infarction. Two patients had concomitant tricuspid annuloplasty and 1 patient mitral valvuloplasty. Result: Surgical mortality was 37.5%(3 patients). They all had only one-vessel disease of left anterior descending artery, which made extended posterior septal wall infarction as well as anterior septal wall infarction of both ventricles. In preoperative M-mode echocardiographic study of left ventricle, they had lower ejection fraction than survivors($34.9{\pm}4.2\;vs.\;54.8{\pm}12.3$; p=0.036). Conclusion: Most of patients with postinfarction VSD had one-vessel disease of left anterior descending artery. Early surgical mortality occurred in the patients with poor ejection fraction of left ventricle and the wide anterior septal wall infarction extending to the posterior septum.

• Archives of Plastic Surgery
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• v.43 no.6
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• pp.586-589
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• 2016

A pressure sore wound is often extensive or complicated by local infection involving adjacent soft tissue and bone. In this case, a regional flap after simple debridement is not adequate. Here, we present a case of an extensive pressure sore in the sacral area with deep tissue infection. A 43-year-old female patient with a complicated sore with deep tissue infection had a presacral abscess, an iliopsoas abscess, and an epidural abscess in the lumbar spine. After a multidisciplinary approach performed in stages, the infection had subsided and removal of the devitalized tissue was possible. The large soft tissue defect with significant depth was reconstructed with a free latissimus dorsi musculocutaneous flap, which was expected to act as a local barrier from vertical infection and provide tensionless skin coverage upon hip flexion. The extensive sacral sore was treated effectively without complication, and the deep tissue infection completely resolved. There was no evidence of donor site morbidity, and wheelchair ambulation was possible by a month after surgery.

• Journal of Chest Surgery
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• v.23 no.1
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• pp.192-200
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• 1990

The results of conventional operative resection of diffuse subaortic stenosis[tunnel subaortic stenosis] have been less than satisfactory. We have performed modified Konno operation to enlarge the outflow tract of both ventricle with a patch in three patients with diffuse tunnel subaortic stenosis in the department of Thoracic and Cardiovascular Surgery, Seoul National University Children`s Hospital. Preoperative left ventricular aortic pressure gradients were 135 mmHg, 50 mmHg, 80 mmHg respectively in these patients. After right ventriculotomy, the septotomy was done and extended beyond the limit of the stenosis and fibrous and/or muscular tissue was removed from each edge of septal incision. After adequate widening of the tunnel subaortic stenosis with various patches, right ventricle was closed primarily or with prosthetic patches successfully. One patient who was diagnosed as complete atrioventricular septal defect had complete AV block preoperatively and was implanted permanent pacemaker, and others who were sinus rhythm preoperatively have no serious postoperative rhythm disturbance. One patient developed mild postoperative aortic insufficiency and one who had preoperative aortic insufficiency has still same grade of aortic insufficiency after operation. All had good postoperative hemodynamics without any postoperative residual pressure gradient.

• Journal of Chest Surgery
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• v.28 no.3
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• pp.237-246
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• 1995

Between March 1989 and December 1994, one-stage repair was performed for correction of the intracardiac malformations associated with aortic coarctation in 34 patients or interrupted aortic arch in 8 patients via median sternotomy. There were 26 male and 16 female patients, and their body weight ranged from 1.8 to 8 kg [mean weight, 4.0 1.4 kg . The age at the operation ranged from 7 days to 18 months [mean age, 3.1 $\pm$ 3.8 months . The repair of aortic coarctation or interrupted aortic arch was performed using extended end-to-end anastomosis in most of the patients [86%, 36/42 , and six patients underwent ductal tissue excision and patch aortoplasty. Intracardiac defects were corrected concomitantly through the right atrium unless the anatomy dictated otherwise. Obstructive outlet septum was resected whenever necessary. There were seven early deaths [16.8 % , and three late deaths with a mean follow-up period of 25 months [range from 1 to 65 months . Three patients were reoperated upon residual subaortic stenosis, stenosis at the RPA origin, and subacute bacterial endocarditis respectively. None showed any significant residual or anastomotic stenosis postoperatively. One stage repair of the aortic coarctation and interrupted aortic arch associated with intracardiac defect leaves no native coarctation shelf tissue or residual hypoplasia in the repaired segment, has low incidence of recurrent or residual stenosis, minimizes reoperation and incisions, and manages arch hypoplasia easily. We concluded that surgical results of one-stage repair for the intracardiac malformation associated with aortic coarctation or interrupted aortic arch are reasonable.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.72-74
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• 2000

This paper presents the linear model of the measurement system with Phasor Measurement Units (PMU's) and the parallel processing technique to determinate state vectors of a power system. The conventional model of the PMU measurement system is in a dilemma that it is not applicable to optimal PMU placements and it needs more PMU to apply this model. In order to improve this defect, in this paper, the extended linear model which adaptable to optimal PMU placements considering the feature of zero injection bus is proposed. Because the proposed model is expressed as over-determined measurement equation, the efficient algorithm is needed. This paper proposed the partitioning scheme and the process algorithm for parallel determinating state vectors of a power system efficiently. The performance of the proposed linear model and the parallel processing algorithm is evaluated with IEEE sample systems.

• Korean Journal of Materials Research
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• v.12 no.6
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• pp.431-435
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• 2002

The dark current and photocurrent(PC) spectrum of Mg-doped GaN thin film were investigated with various bias voltages and temperatures. At high temperature and small bias, the dark current is dominated by holes thermally activated from an acceptor level Al located at about 0.16 eV above the valence band maximum $(E_v)$, The PC peak originates from the electron transition from deep level A2 located at about 0.34 eV above the $E_v$ to the conduction band minimum $(E_ C)$. However, at a large bias voltage, holes thermally activated from A2 to Al experience the field-in-duces tunneling to form one-dimensional defect band at Al, which determines the dark current. The PC peak associated with the transition from Al to $E_ C$ is also observed at large bias voltages owing to the extended recombination lifetime of holes by the tunneling. In the near infrared region, a strong PC peak at 1.20 eV appears due to the hole transition from deep donor/acceptor level to the valence band.

• Transactions of Materials Processing
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• v.27 no.5
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• pp.289-295
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• 2018

The profile ring rolling process can realize various ring shapes unlike conventional rectangular cross-sectional ring products. In this paper, the defective groove in the bottom surface of L-shaped ring products was analyzed. Grooves are generated by non-uniform external forces due to profile main roll and initial blank shape. Process parameters such as the motion of dies and working temperature were determined. Mechanism of groove formation was analyzed by FE simulation on the basis of local external forces acting on the blank. Analysis results were similar to the groove actually occurring in the production line. Based on results of the analysis, two solutions were proposed for the groove. The position of the base plate supporting the blank was adjusted and edge length of the main roll was extended to suppress growth of grooves. It has been verified that groove was improved by applying two proposed methods in the shop-floor.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.5 s.248
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• pp.533-542
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• 2006

In order to assess the integrity of pipes with local thinning area, the plastic strain as well as the elastic strain at the root of thinned region are required particularly when fluctuating load is applied to the pipe. For estimating elastic-plastic strain at local wall thinning area in a straight pipe under tensile load, an estimation model with idealized fully circumferential constant depth wall thinning area is proposed. Based on the compatibility and equilibrium equations a nonlinear estimation equation, from which local elastic-plastic strain can be determined as a function of pipe/defect geometry, material and the applied strain was derived. Estimation results are compared with those from detailed elastic-plastic finite element analysis, which shows good agreements. Noting that practical wall thinning in nuclear piping has not only a circular shape but also a finite circumferential length, the proposed solution for the ideal geometry is extended based on two-dimensional and three-dimensional numerical analysis of pipes with circular wall thinning.