• The KIPS Transactions:PartC
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• v.13C no.3 s.106
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• pp.353-358
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• 2006

Unlike TCP Reno, TCP Vegas recognizes network congestion through the measuring of RTT (Round Trip Time) and decides the main congestion control parameters, such as Windows size. But, congestion avoidance scheme of Vegas poorly reflects asymmetric characteristics of packet path because TCP Vegas uses the measuring of RTT that reflects forward/backward packet transmission delay as a forward delay. The RTT can't infer the forward/backward transmission delay variation because it only measures the packet's turn around time. In this paper, We have designed and implemented a new Vegas congestion control algorithm that can distinguish forward/backward network congestion. We have modified the source codes of TCP Vegas in Linux 2.6 kernel and verified their performance.

• Korean Journal of Construction Engineering and Management
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• v.20 no.1
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• pp.133-140
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• 2019

The concrete mix should be designed and produced to reflect the specific site conditions during concrete placement. That is, the concrete mix design should be planned considering temperatures, work environments, pouring methods, etc. The objective of this research is to understand the external factors of curing temperature and delay time that influence concrete strengths during pouring work, and provide concrete mix design that can be most robust to the effects of external factors. The Taguchi's robust method is used in preparing the concrete mix design to achieve the research objective. In a case study, an indoor concrete test was performed to find the optimal combination of concrete mixes with external factors of curing temperature and delay time. Concrete test cylinders were made to test concrete strengths given different external factors. The study results showed that the optimal performance of concrete strength can be achieved by applying the robust method when preparing a concrete mix design.

• Economic and Environmental Geology
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• v.55 no.6
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• pp.563-570
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• 2022

This study was objected to show the complexity of groundwater flow system in a site-scale area as a design parameter of the groundwater monitoring network for early detection of pollutant leakage from a potential source of groundwater contamination (e.g., storage tank). Around the tanks, three monitoring wells were installed at about 22~25 m deep and groundwater level and temperature had been monitored for 22 months by 2-minute interval, and then compared with precipitation and temperature data from nearby weather station. Annual variation of groundwater level and its response to precipitation event, variation of groundwater temperature and delayed response to that of atmospheric temperature indicate the complexity of groundwater flow and flow paths even in the relatively small area. Thus, groundwater monitoring network for early detection of contaminant leakage should be designed with full consideration of the complexity of groundwater flow system, identified from the detailed hydrogeological investigation of the site.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.589-594
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• 2005

With the progress of medical treatment techniques of bleeding control, dental care of the patient with hemophilia has become more convenient. So many surgical treatments can be performed with out-patient. 2 cases of intraoral surgical treatment of children, one with hemophilia 3, sever, the other with hemophilia A, severe. While the former was treated under general anesthesia, the latter was treated under local anaesthesia. There are principles : 1. When a patient with hemophilia need dental treatment, the dentist must consult to his physician, pediatrician, or hematologist before dental treatment. 2. When the dentist make a treatment plan, there should be consideration of the general condition, cooperation of the patient and risk of the treatment needed. 3. Minimize the number of times of coming for dental treatment so that reduce the times that need replacement therapy of coagulation factor. And during the treatment, dentist should care for infection and bleeding.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.4
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• pp.53-59
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• 2011

In this study, as a tool of evaluating biological stability of landfilled waste, influencing factors of $AT_4$ method was studied for standardizing the method. As influencing factors, initial lag time, exchanging period of $CO_2$ absorbing agent, and interval of pressure measurement were discussed, and also the relationship between content of dried food waste and $AT_4$ value were compared. Considering heterogeneity of landfilled waste and statistical error range of measurement, authors suggest that the criteria of stabilized landfill waste is $10mg\;O_2/g\;DM$ by $AT_4$ method.

• Journal of the Korea Convergence Society
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• v.10 no.6
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• pp.243-249
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• 2019

This study was conducted on elderly women in their 60s and 70s, and the results of the study were as follows when line dancing for 60 minuctes every three times a week for 12 weeks on dementia and aging-related hormones. After 12 weeks of line dancing programs, BDNF, DHEA-s, and estrogen increased, but no statistically significant differences with control groups emerged. In addition, after 12 weeks of line dancing, Apolipoprotein B decreased in line dancing group but showed no statistically significant difference from control group. Although significant differences between groups were not identified in the results of this study, positive effects on preventing and aging of dementia were identified in the group applying the line dance program, and further studies considering the new target and hign kinetic strength, frequency, time, and athletic genre are needed to identify the distinct effects of line dancing in the future.

• Journal of Chest Surgery
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• v.37 no.5
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• pp.391-400
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• 2004

Xenotransplantation in discordant species results in immediate and irreversible hyperacute rejection due to natural antibodies, IgM. With this, antibody depletion is one option to reduce hyperacute rejection, we investigated the effect of PCPP (postcentrifugal plasmapheresis) on the depletion of natural antibodies and the effect of antibody titer on xenograft survival. Material and Method: Outbred swines (n=4) weighing 10∼20 kg were used as donors and mongrel dogs (n=4) weighing 25∼30 kg were used as recipients. Recipient canines underwent plasmapheresis (COBE TPE Laboratories, Lakewood. CO, USA). Pre-transplantation PCPP was peformed on day －2 and day 0. There were three groups (Group 0: no PCPP, Group 1: 1 pla sma-volume (PV) at day －2 and 2 PV at day 0, Group 2: 2 PV at day －2 and 2 PV at day 0). A swine heart was heterotopically transplanted into a recipient's abdominal infrarenal aorta and inferior vena cava. Mean percent depletion of total IgM and IgG in plasma of the recipients was calculated. Serum albumin, electrolyte, complement activity and coagulation factors were measured. Histopathologic examination of heart specimens was performed. Result: Mean percent depletion of IgM and IgG were 95.7$\pm$1.2%, 80.5$\pm$2.4% in the group 2 at the end of PCPP. The percent depletion of serum albumin concentration was decreased from 2.8 to 1.4 g/㎗ in the group 1 and 3.0 to 1.5 g/㎗ in the group 2. Complement hemolytic activity was decreased in group 1 and 2, but returned to normal level within 24 hours. Complement hemolytic activity was reduced to 10% of pre-PCPP level in group 2. Serum fibrinogen decreased to 20% or less and was recovered within 24 hours in group 2. Antithrombin III decreased but less than fibrinogen. PT and aPTT were sometimes but not always prolonged during plasmapheresis. After plasmapheresis, PT and aPTT were prolonged beyond the measurable level. D-dimer was not found during PCPP, but appeared and maintained from 10 minutes after trasplantation. Graft Survival time was 5 min in group 0, and it was 90$\pm$0 min in the group 2. Histopathologic changes were more typically characterized by edema, hemorrhages, thrombosis in all groups at the end of experiment. Conclusion: PCPP effectively removed immuoglobulins and reduced the titer of natural antibodies, as a result, significantly prololonged swine heart xenograft survival.

• Journal of Chest Surgery
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• v.32 no.9
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• pp.790-798
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• 1999

Background: As the early outcome after coronary artery bypass grafting(CABG) has been stabilized, neurologic complication has now become one of the most important morbidity. The aim of this study was to find out the risk factors associated with the neurologic complications after CABG. Material and Method: In 351 patients who underwent CABG, the incidence and features of neurologic complications, with associated perioperative risk factors, were retrospectively reviewed. Neurologic complication was defined as a new cerebral infarction confirmed by postoperative neurologic examination and radiologic studies, or delayed recovery of consciousness and orientation for more than 24 hours after the operation. Result: Neurologic complications occurred in 18 patients(5.1%), of these nine(2.6%) were diagnosed as having new cerebral infarctions(stroke). Stroke was manifested as motor paralysis in four patients, mental retardation or orientation abnormality in four, and brain death in one. Statistical analysis revealed the following variables as significant risk factors for neurologic complications by both univariate and multivariate analyses: cardiopulmonary bypass longer than 180 minutes, atheroma of the ascending aorta, carotid artery stenosis detected by Duplex sonography, and past history of cerebrovascular accident or transient ischemic attack. Age over 65 years, aortic calcification detected by simple X-ray, and intraoperative myocardial infarction were significant risk factors by univariate analysis only. Neither the severity of carotid artery stenosis nor technical modifications such as cannulation of the aortic arch or single clamp technique, which were expected to affect the inciden e of neurologic complications, had significant relationship with the incidence. Conclusion: This study confirmed the strong association between neurologic complications after CABG and atherosclerosis of the arterial system. Therefore, to minimize the incidence of neurologic complications, systematic evaluation focused on atherosclerotic lesions of the arterial system followed by adequate alteration of operative strategy is needed.

• The Korean Journal of Nuclear Medicine
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• v.37 no.2
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• pp.128-134
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• 2003

섬유성 골이형성증은 비정상적인 섬유성 골조직으로 대체되며 느리게 진행하는 골병변이다. 섬유성 골이형성증과 부갑상선기능항진증은 흔하게 관찰되는 질환이나 McCune-Albright 증후군 없이 일차성 부갑상선기능항진증에 동반된 섬유성 골 이형성증은 거의 보고된바가 없다. Tc-99m MDP 골스캔이 섬유성 골이형성증의 진단에 유용하다고 알려져 있으나, Tc-99m MIBI 영상은 아직 보고된 바가 없다. 저자들은 McCune-Albright 증후군이 없이 부갑상선기능항진증에 동반된 섬유성 골 이형성증의 Tc-99m MIBI 스캔과 Tc-99m MDP 골스캔의 영상을 비교하였다. Tc-99m MDP 골스캔상 병변 부위에서 증가된 섭취 소견을 보였으며, Tc-99m MIBI 조기영상에서도 동일한 위치에서 섭취증가가 관찰되었다. 2시간 지연 Tc-99m MIBI 영상에서는 Tc-99m MIBI의 섭취가 배출되는 소견을 보였다. 섬유성 골이형성증 병변에서 Tc-99m MIBI 스캔이 유용할 것이라고 생각하며, 섬유성 골이형성증 병변에서 Tc-99m MIBI의 섭취를 증가시키는 인자에 대한 더 많은 연구가 필요할 것으로 생각한다.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.10
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• pp.556-568
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• 2003

This paper presents and analyzes the performance of a weighted-window based cache replacement policy for the efficient media caching in streaming media cache servers. The proposed policy makes, for each cached object, use of the reference count, reference time, amount of media delivered to clients and, in particular, the periodic patterns of user requests. Also, by giving weights to the recently referenced media contents, the replacement policy adequately and swiftly reflects the ever-changing characteristics of users preferences. The simulation studies show that the performance of the proposed policy has improved over the conventional policies such as LRU, LFU and SEG - in terms of hit ratio, byte hit ratio, delayed start and cache input.