• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.281-286
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• 2002

To study of binder and fine aggregate a lot of replacement fly-ash concrete, initial characteristics, standard environment of curing temperature $20^{\circ}C$, hot-weather environment of curing temperature $35^{\circ}C$, . Flesh concrete tested slump. air contest and Hardening concrete valuated setting period of form, day of age 1, 3, 5. 7, 10, 28 compression strength in sealing curing. Purpose of study is consultation materials in field that variety of fly-ash replacement concrete mix proportion comparison and valuation. (1) Experiment result age 28day compression strength more higher plan concrete then standard environment in curing temperature $20^{\circ}C$, , most strength F43 is hot-weather environment in curing temperature $35^{\circ}C$, replacement binder 25%, fine aggregate 15%. (2) Hot-weather environment replacement a mount of fly-ash is a same of plan concrete setting period of form. Age 28day compression strength replacement a mount of fly-ash more hot-weather concrete then plan concrete.

• The Journal of Korean Physical Therapy
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• v.25 no.6
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• pp.417-421
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• 2013

Purpose: This study was to identify the effect of cervical stabilization exercise on pain and structure in patients with cervical artificial disc replacement. Methods: Forty-four individuals with cervical artificial disc replacement volunteered to participate from FEB 2012 to MAR 2013 in this study. They were allocated to either Experimental Group (EG) or Control Group (CG), with 22 subjects in each group. Subjects from the EG performed cervical stabilization exercise program and subjects from the CG performed isometric exercise program. Assessment tools were made with the Visual Analogue Scale (VAS), Neck Disability Index (NDI), and Cervical Lordosis Angle (CLA). Results: In this study, in within-group and between-group comparison, the EG and CG showed significant differences in all parameters(p<0.05). But EG showed more improvement than CG at all parameters. Conclusion: These findings suggest that cervical stabilization exercise may be favorably used to improve VAS, NDI and CLA in patients with cervical artificial disc replacement. Further studies with larger sample and long-term follow-up period need to generalize the results of this study.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2691-2696
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• 2013

The electronic cigarette (E-cigarette) is a battery-powered device that aerosolizes nicotine so that it is readily delivered into the respiratory tract. The analytical data regarding the substances present in E-cigarettes are very limited. The aim of this study was to measure the concentration of aldehydes-formaldehyde (FA), acetaldehyde (AA) and, acrolein (AL)-in 225 replacement liquid brands from 17 E-cigarette shops sold in the Republic of Korea by headspace solid-phase micro extraction and gas chromatography-mass spectrometry (HS-SPME GC-MS). The concentration range of FA and AA was 0.02-10.09 mg/L (mean = 2.16 mg/L, detected in 207 of 225 samples) and 0.10-15.63 mg/L (mean = 4.98 mg/L, detected in all samples), respectively. AL was not detected in any of 225 replacement liquids. FA and AA were originally present in almost all replacement liquids of electronic cigarettes.

• Journal of Korean Institute of Industrial Engineers
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• v.14 no.1
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• pp.103-117
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• 1988

Replacement demand plays an important role to forecast the total demand of durable goods, while most of the diffusion models deal with only adoption data, namely initial purchase demand. This paper presents replacement demand forecasting models incorporating repurchase rate, multi-ownership, and dynamic product life to complement the existing diffusion models. The performance of replacement demand forecasting models are analyzed and practical guidelines for the application of the models are suggested when life distribution data or adoption data are not available.

• Journal of Korean Society for Quality Management
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• v.32 no.3
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• pp.62-67
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• 2004

This paper presents and compares two block replacement policies under random use durations. The units are put in service altogether and then idle for some time. The time durations during which units are put in service are random variables. Two block replacement policies, called N-policy and T-policy, are presented. Under N-policy, units are replaced altogether after the Nth use. Under T-policy, units are replaced altogether at the end of the use after cumulative use time T elapses. The failures during use durations are replaced by new ones individually. The cost rate expressions under the policies are derived for exponential use durations. Numerical examples are presented to compare the performances of the two policies.

• Journal of Korean Society for Quality Management
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• v.12 no.2
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• pp.2-5
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• 1984

Periodic replacement model with minimal repair at failure is extended to the case where quantity purchases are possible. A recursive relationship among replacement intervals is obtained, which shows that replacement intervals are an increasing sequence due to the inventory carrying cost. Using the relationship, a procedure is given for determining how many units to purchase on each order and when to replace each unit after it has begun operating so as to minimize the total cost per unit time over an infinite time span. The problem can be simplified if equal replacement intervals are assumed, and the solution is very close to the solution of the unconstrained problem.

• Journal of Chest Surgery
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• v.11 no.3
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• pp.281-295
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• 1978

Last year in this department 100 cases of open heart surgery were done annually. This year 200 cases of open heart surgery were scheduled. During the first 6 months of this year 112 open heart surgery cases were done with 13 deaths [11.6%]. There were 72 cases of cougenital malformation with 9 operative deaths [12.5%], consisting of 23 acyanotic cases with one death [4.5%] and 49 cases of cyanotic cases with 8 deaths [16.3%]. Out of 40 tetralogy of Fallot, 6 cases expired [15%]. For 39 cases of acquired valvular heart disease and one Ebstein anomaly valves were replaced with 4 operative deaths [10%]. Single valve replacement in 33 with 3 operative deaths and double valve replacement in 7 cases with one death were noted. Two patients expired among 28 mitral valve replacement cases [7.1%]. Among 7 double valve replacement patients, consisting of 3 mitral and aortic and 4 mitral and tricuspid valve replacement one case expired. In a case of Ebstein anomaly, tricuspid valve was replaced with plication of atrialized right ventricle successfully. The operative result was excellent.

• Journal of Korean Society for Quality Management
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• v.40 no.1
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• pp.88-91
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• 2012

Joint optimization of preventive age replacement and inventory policy is considered in this paper. There are three decision variables in the problem: (i) preventive replacement age of the operating unit, (ii) order quantity per order and (iii) reorder point for spare replenishment. Preventive replacement age and order quantity are jointly determined so as to minimize the expected cost rate, and then the reorder point for meeting a desired service level is found. A numerical example is included to explain the joint optimization model.

• Journal of Chest Surgery
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• v.11 no.2
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• pp.185-193
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• 1978

Between April 1976 and March 1978, six cases of tricuspid valve replacement were done in the Department of Thoracic Surgery, Seoul National University Hospital. There were 4 men and 2 women and the age of the patients ranged from 17 years of the youngest to 48 years of the oldest. Most of them had characteristic symptoms of tricuspid valve disease, such as a systolic murmur audible over the lower sternum and varying with respiration, pulsatile and distended neck vein, and an enlarged and pulsatile liver. Preoperative functional levels according to NYHA Calcification were class III in 4 cases, and class IV in 2 eases. Most of the cases showed moderate to severe cardiomegaly in chest films and elevated right atrial pressure on preoperative right heart catheterization. Five of them underwent concomittent mitral valve replacement and one pulmonary valvotomy. All of them showed tricuspid insufficiency resulted from massive dilatation of annulus, destructive lesions of valve structure, or both anomalies. One postoperative hospital death was encountered and the cause of death was low out-put syndrome. All survivors showed clinical improvement and cardiomegaly regressed and left hospital in a good condition . *Attendum; Recently 2 more cases of tricuspid valve replacement with mitral valve replacement were done after this review.

• Journal of Chest Surgery
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• v.11 no.2
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• pp.199-212
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• 1978

One hundred cases of cardiac valve replacement were done at this Department in the period from June 1968 to May 15, 1978. Seventy-one cases of mitral, 12 aortic, and one tricuspd valve were replaced. There were 16 cases of double valve replacement, 10 aortic with mitral and 6 mitral with tricuspid valve replacement. Prosthetic valves-Beall, Bjoerk-Shiley, Starr-Edwards, Wada-Cutter, Magovern-Cromie, and Smeloff-Cutter valves-were used. But in recent years bioprosthetic valves-Hancock, Carpentier-Edwards, and Angell-Shiley valves-were used mainly due to the difficulties of postoperative anticoagulation, especially for the rural Korean patients. Over all operative mortality was 2896, 26.2% for single and 37.5% for double valve replacement cases. There were 4 postoperative thrombo-embolism cases with 2 deaths. Four postoperative subacute bacterial endocardities cases with 2 deaths were noted. Three cases of postoperative congestive heart failure succumbed. Two cases of peri valvular leakage, one of which needs reopration, were found. There were 28 operative and 9 late deaths, leaving 63 long-tel m survivors, who showed marked improvements.