• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.5B
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• pp.435-447
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• 2003

Current existing network dimensioning method simply relies on long-time measurement data or uses average traffic characteristics of users. In this paper, we propose an efficient network dimensioning method for DiffServ over MPLS networks. First, User's SLA information is distributed from edge nodes to core nodes according to the proposed algorithm. Then at each link, class-based capacity planning is performed. For capacity planning, we proposed sets of network design parameters for DiffServ classes and bandwidth allocation schemes that are most suitable for each class. We have developed a DiffServ over MPLS network design tool using the proposed method. Simulation results show that our proposed method is able to design efficiently the required class link resources.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.132-138
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• 2022

In this study, a basic study was performed to systematically compare the changes in surface properties according to the post-processing method of the stereolithography (SLA) printing method, which is a photocuring 3D printing method, and to provide information on the post-processing method suitable for the application. Although it was possible to improve some of the transparency of the SLA-type output by regularly changing the irregular microstructure of the surface through polishing, it was difficult to secure sufficient transparency like glass. The change in contact angle characteristics due to grinding showed a tendency to slightly increase as the grinding time increased and the particle size of the sandpaper used was small, but the variation between samples was large and the average contact angle was 77~90°, showing no statistically significant difference. Surface treatment methods other than polishing were tried, and it was confirmed that it was possible to easily and simply improve the transparency by applying a commercially available vehicle scratch remover or silicone oil. In addition, a method for securing high transparency such as glass by using a scratch remover after sequential grinding while reducing the particle size of the sandpaper was proposed. Finally, even after surface treatment through polishing and various methods, it was difficult to secure a contact angle of 90° or more.

• The KIPS Transactions:PartD
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• v.14D no.3 s.113
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• pp.319-328
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• 2007

As the coverage of Web services become wider and the number of implementation cases is growing, the importance of applying the Web services quality model to real world is increased. For maintaining the level of Web services qualify, it should be required to study on assurance method of Web services qualify level. Assurance for Web services, which is newly proposed by OASIS TC, means the totality of activities for managing the quality level of them. For managing Web service quality, Web service associates could usually use SLA(Service Level Agreement) method in which a service consumer contracts for some service level with a service provider and gives for penalty or pays incentives according to the result of evaluation of services. But, there are some difficulties in applying SLA to Web services, because Web services have publicity, multiple users, and 3rd party for management. So, we need a new assurance method for Web service by considering the characteristics of Web services. This paper provides the new concept of committed assurance level for Web services. This concept can be defined as the set of maximum level of quality expected by each user, which provide the consistent view of Web service quality. This paper presents the method for duality associates to preserve some quality level of Web service by using this concept.

• Journal of Korean Neurosurgical Society
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• v.59 no.6
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• pp.610-614
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• 2016

Objective : The purpose of this study was to present the outcome of the microsurgical foraminotomy via Wiltse paraspinal approach for foraminal or extraforaminal (FEF) stenosis at L5-S1 level. We investigated risk factors associated with poor outcome of microsurgical foraminotomy at L5-S1 level. Methods : We analyzed 21 patients who underwent the microsurgical foraminotomy for FEF stenosis at L5-S1 level. To investigate risk factors associated with poor outcome, patients were classified into two groups (success and failure in foraminotomy). Clinical outcomes were assessed by the visual analogue scale (VAS) scores of back and leg pain and Oswestry disability index (ODI). Radiographic parameters including existence of spondylolisthesis, existence and degree of coronal wedging, disc height, foramen height, segmental lordotic angle (SLA) on neutral and dynamic view, segmental range of motion, and global lumbar lordotic angle were investigated. Results : Postoperative VAS score and ODI improved after foraminotomy. However, there were 7 patients (33%) who had persistent or recurrent leg pain. SLA on neutral and extension radiographic films were significantly associated with the failure in foraminotomy (p<0.05). Receiver-operating characteristics curve analysis revealed the optimal cut-off values of SLA on neutral and extension radiographic films for predicting failure in foraminotomy were $17.3^{\circ}$ and $24^{\circ}s$, respectively. Conclusion : Microsurgical foraminotomy for FEF stenosis at L5-S1 level can provide good clinical outcomes in selected patients. Poor outcomes were associated with large SLA on preoperative neutral (>$17.3^{\circ}$) and extension radiographic films (>$24^{\circ}$).

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.1
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• pp.71-84
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• 2007

Statement of problem: Implant surface characteristics plays an important role in clinical success and many studies have been made for improvement of success by changing surface roughness. Purpose: Appropriate increase of surface roughness increases the activity of osteoblast and enhance contact and retention between bone and implant. Material and method- Machined, SLA and RBM surface implants, which are the most commonly used implants were implanted into the tibia of rabbits and after 1 week, 4 weeks, 8 weeks and 12 weeks there were histologic and histomorphometric analysis and study for bone gradient and change of Ca/P ratio using EDS(Energy Dispersive X-ray Spectroscope). Results: Comparison of bone-implant contact showed no significant difference among each implant. In comparison of bone area rates, SLA showed higher value with significant difference at 1 week and 4 weeks, and SLA and RBM at 8 weeks than Machined implant (p<0.05). In analysis of bone constituents with EDS, titanium was specifically detected in new bones and the rates were constant by surface treatment method or period. In case of Ca/P ratio, according to surface treatment method, each group showed significant difference. Lots of old bone fragments produced during implantation remained on the rough surface of RBM implant surface and each group showed histological finding with active synthesis of collagen fibers until 12 weeks. In transmission electronic microscopic examination of sample slice after elapse of twelve weeks, tens nm of borderline (lamina limitans like dense line)was seen to contact the bone, on the interface between bone and implant. Conclusion: SLA and RBM implant with rough surface shows better histomorphometrical result and the trend of prolonged bone formation and maturation in comparison with Machined implant. In addition, implant with rough surface seems to be helpful in early stage bone formation due to remaining of old bone fragments produced in implantation. From the results above, it is considered to be better to use implant with rough surface in implantation.

• Journal of Life Science
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• v.20 no.7
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• pp.1127-1133
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• 2010

The total photosynthetic rate in leaf mustard lines, which was calculated as the sum of the photosynthetic rate and the respiration rate, was not significantly different from their photosynthetic rate. Plant height, standing of rosetteness, showed a similar change to its specific leaf area (SLA). With increasing the plant height, leaf density increased and leaf color was lighter. It was found that shoot dry weight of leaf mustard was more affected by respiration. Also, it was hypothesized that respiration occurred not only in the leaf but also the stem. It was found that mustard lines whose leaf density was low showed a higher shoot growth. From this result, it was concluded that selection of a leaf mustard line with a larger SLA and lower leaf thickness could be effective in increasing photosynthetic rate.

• Korean Chemical Engineering Research
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• v.57 no.5
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• pp.706-713
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• 2019

In this study, basic research was conducted to provide guidelines for selecting printers and materials suitable for each application case by analyzing 3D printing method and surface characteristics of materials suitable for microfluidic system. We have studied the surface characteristics according to the materials for the two typical printing methods: The most commonly used method of Fused Deposition Modeling (FDM) printing and the relatively high resolution method of Stereolithography (SLA) printing. The FDM prints exhibited hydrophilic properties before post - treatment, regardless of the material, but showed hydrophobic properties after post - treatment with acetone vapor. It was confirmed by the observation of surface roughness using SEM that the change of the contact angle was due to the removal of the surface structure by post-treatment. SLA prints exhibited hydrophilic properties compared to FDM prints, but they were experimentally confirmed to be capable of surface modification using hydrophobic coatings. It was confirmed that it is impossible to make a transparent specimen in the FDM method. However, sufficient transparency is secured in the case of the SLA method. It is also confirmed that the electroporation chip of the digital electroporation system based on the droplet contact charging phenomenon was fabricated by the SLA method and the direct application to the microfluidic system by demonstrating the electroporation successfully.

• Journal of Information Technology Applications and Management
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• v.10 no.3
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• pp.75-92
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• 2003

In order to investigate IS(Information Systems) outsourcing cost estimation model preference of firms, this study reviews previous literatures on outsourcing and firm characteristics. The relationships between firm characteristics and IS outsourcing cost estimation model preference are analysed. Four major factors of firms characteristics are found and classified. IS outsourcing cost estimation model with SLA are found to have a strong relationship with organizational culture. Future research will be needed to verify the result of this exploratory study.

• Journal of Korea Multimedia Society
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• v.20 no.7
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• pp.1030-1037
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• 2017

Traffic flows of real-time multimedia services such as Internet phone and IPTV are bounded on the end-to-end delay. Packets violating their delay limits will be dropped at a router because of not useful anymore. Service providers promise the quality of their providing services in terms of SLA(Service Level Agreement), and they, especially, have to guarantee the packet loss rates listed in the SLA. This paper is about a method to guarantee the required packet loss rate of each traffic flow keeping the high network resource utilization as well. In details, it assures the required loss rate by adjusting adaptively the timestamps of packets of the flow according to the difference between the required and measured loss rates in the lossy Weighted Fair Queuing(WFQ) scheduler. The proposed method is expected to be highly applicable because of assuring the packet loss rates regardless of the fluctuations of offered traffic load in terms of quality of services and statistical characteristics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.649-650
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• 2013