• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10A
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• pp.1517-1531
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• 1999

The Internet is recently evolving into the directions which is capable of incorporating stream-type services such as voice and video services. However, the existing Internet can only support a best-effort delivery model and thus it is difficult to satisfy these requirements as well as to provide the QoS beyond a certain degree. Accordingly, it is imperative to develop QoS based routing algorithm in order to allow the routing by the user's QoS demand and to be applied into wide area networks. In this thesis, we presented new routing algorithms and made performance evaluations. The proposed algorithms allow the routing by the user’s QoS demand level in order to provide the diverse Internet application services based on ATM network environment that is expected to play a role as an infrastructure of high-speed communication network. They also have a feature of shortening the waiting time for address analysis and have a quality-proven characteristics with enhanced network scalability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11C
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• pp.33-42
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• 2001

We consider a model describing large scale performance of multiservice networks supporting both constant- and adaptive-rate services. As the number of constant-rate connection changes over time in multiservice networks, the available bandwidth for adaptive-rate connections changes as well. We estimate the available bandwidth for adaptive-rate service in a dynamically changing traffic environment based on Erlang fixed point equation and Little\`s law. The bandwidth allocation for adaptive-rate service is determined by the max-min fairness criterion. We find an upper bound on the average minimum throughput for adaptive-rate service, and 7how that the bound is achieved in large-capacity networks. This is verified using network examples. Since max-min fair allocation may not maximize the total throughput or revenue in a network, we consider adjustments via network level priority schemes to increase efficiency.

• Clinics in Shoulder and Elbow
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• v.23 no.2
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• pp.86-93
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• 2020

Background: Several systematic reviews have reported on the conservative treatment of full-thickness rotator cuff tears; however, clinical results of this treatment still remain determined. Methods: PubMed, Cochrane Library, PEDro, and CINAHL databases were systematically searched for randomized clinical trials and observational studies. Two independent researchers reviewed a total of 2,981 articles, 28 of which met the criteria for inclusion in the study. Clinical outcome measures included Constant score, visual analog scale score for pain, range of motion, and short-form 36 questionnaires. The meta-analysis used a linear mixed model weighted with the variance of the estimate. Results: The meta-analysis showed a significant improvement after surgery. Pain score is 26.2 mm (1 month) to 26.4 mm (3 months), and 24.8 mm (12 months) (P<0.05); active abduction: 153.2° (2 months), 159.0° (6 months), 168.1° (12 months) (P<0.05); Constant score: 67.8 points (2 months) to 77.2 points (12 months) (P<0.05); short-form 36 questionnaires "vitality" section: 57.0 points (6 months) to 70.0 points (12 months) (P<0.05). Conclusions: Our data confirmed the effectiveness of conservative treatment in patients with full-thickness rotator cuff tears 12 months post-intervention. The results suggest that conservative treatment for patients with full-thickness rotator cuff tears should be the first line of treatment before considering surgery.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.8
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• pp.1098-1102
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• 2018

Objective: Temperament can be defined as a type of behavioral tendency that appears in a relatively stable manner in responses to various external stimuli over time. The aim of this study was to estimate genetic parameters for the records of temperament testing that are used to improve the temperament of Jeju crossbred (Jeju${\times}$Thoroughbred) horses. Methods: This study was conducted using 205 horses (101 females and 104 males) produced between 2010 and 2015. The experimental animals were imprinted and tamed according to the Manual for Horse Taming and Evaluation for Therapeutic Riding Horses and evaluated according to the categories for temperament testing (gentleness, patience, aggressiveness, sensitivity, and friendliness) between 15 months and 18 months of age. Each category was scored on a five-point linear scale. Genetic parameters for the test categories were analyzed using a multi-trait mixed model with repeated records. The ASReml program was used to analyze the data. Results: The heritability of gentleness, patience, aggressiveness, sensitivity and friendliness ranged from 0.08 to 0.53. The standard errors of estimated heritability ranged from 0.13 to 0.17. The test categories showed high genetic correlations with each other, ranging from 0.96 to 0.99 and high repeatability, ranging from 0.70 to 0.73. Conclusion: The results of this study showed that the test categories had moderate heritability and high genetic correlations, but additional studies may be necessary to use the results for the improvement programs of the temperament of Jeju crossbred horses.

• Journal of the Korean Geosynthetics Society
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• v.16 no.4
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• pp.163-176
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• 2017

The Discrete Element Method (DEM) has been widely used in civil engineering as well as various industrial fields to simulate granular materials. In this study, DEM was adopted to predict the performance of the face plate-type earth pressure balance (EPB) shield TBM (Tunnel Boring Machine). An analysis of the TBM excavation performance was conducted according to two pre-defined excavation conditions with the different rotation speeds per minute (RPM) of the cutterhead. The TBM model which was used in this study has a 6.64 m of diameter and six spokes. Also, 37 precutters and 98 scrapers at an each spoke were modeled with a real-scale specification. From the analysis, compressive forces at the cutterhead face, shield and cutting tools, resistant torques at the cutterhead face, muck discharge rate and accumulated muck discharge by the screw auger were measured and compared.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.396-401
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• 2004

In this paper, a 1MW HAWT(FIL-1000) rotor blade has been designed by BEMT(Blade Element Momentum Theory) with Prandtl's tip loss. Also, a 3-D flow and performance analysis on the FIL-1000 rotor blade has been carried out by using the 3-D Navier-Stokes commercial solver (CFX-5.7) to provide more efficient design techniques to the large-scale HAWT engineers. The rated power and itsapproaching wind velocity at design point (TSR=7.5) are 1MW and 9.99m/s respectively. The rotor diameter is 54.5m and the rotating speed is 26.28rpm. Airfoils such as FFA W-301, DU91-W-250, DU93-W-210, NACA 63418, NACA 63415 consist of the rotor blade from hub to tip. Recent CFX version, 5.7 was adopted to simulate 3-D flow field and to analyze the performance characteristics of the rotor blade. Entire mesh node number is about 730,000 and it is generated by ICEM-CFD to achieve better mesh quality The predicted maximum power occurringat the design tip speed ratio is 931.45kW. Approaching to the root, the inflow angle becomes large, which causesthe blade to be stalled in the region. Therefore, k-$\omega$ SST turbulence model was used to predict the quantitative flow information more accurately. Application of commercial CFD code to optimum blade design and performance analysis was proved to be more effective environment to HAWT blade designers.

• Physical Therapy Korea
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• v.19 no.2
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• pp.48-58
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• 2012

The objective of this study was to evaluate the effects of mirror therapy on motor function recovery following a stroke through a systemic review and meta-analysis. In total, nine of the 48 studies were identified from search engines between 1997 and 2011, as well as from a review of the reference lists of each identified study. The quality of each study was assessed using Jadad scale, and the effect size was calculated as a Cohen's effect size using MetaAnalyst (Beta 3.13). The overall effect size of the mirror therapy was 2.005 (95% confidence interval=1.041~2.970) in a random-effects model. This finding suggests that mirror therapy is beneficial for improving motor function following a stroke. The results from the subgroup analysis according to categorical variables were as follows: First, the effect size was larger for an onset time of less than 1 year (1.166) than for a duration of 1 year or more (.668). Second, the effect size of unpublished dissertations (1.610) was larger than published articles (1.221). Third, motor recovery of upper extremities (1.609) had a greater effect than motor recovery of lower extremities (.903). The major limitation of this study is the relatively small study population. Therefore, further individual studies of mirror therapy should be conducted in order to generalize the effects. In addition, mirror therapy supervised by a physical therapist should be recognized as a potential approach to manage motor function following a stroke and recommended to patients to improve their motor function.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.2
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• pp.55-66
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• 1999

Eight RC bridge plers have been made on a 1/3.4 scale model and have been tested in a quasi-static cyclic load so as to investigate their seismic performance. The ultimate objective of this experimental study is to investigate the hysteretic behavior of reinforced concrete plers, which have been widely used for urban transportation facilities in Korea. Improtant test parameters are hoop ratio, axial load, load pattern, and etc. And noninear behaviors of test columns have been evaluated through their yield and ultimate strength, energy dissipation, ductility and load-deflection characteristics under quasi-static cyclic loads. From the quasi-static tests on 8 bridge piers, it is concluded that energy dissipation, ultimate strength and curvature for a given displacement factor ${\mu}={\Delta}/{\Delta}_y$ are higher for the seismically designed columns than for the nonseismically designed columns.

• Informatization Policy
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• v.19 no.2
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• pp.85-105
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• 2012

So far, the importance of informatization, as well as investment into it, has been growing steadily. Due to the uncertainties and risks in adopting information technologies, systematic decision-making is definitely needed in investing in a large scale information system. Based on the existing theories about the economic life span of information systems and in consideration of the actual cost involved in the adoption and operation of the systems by the financial institutions in Korea, this study presents the optimal economic life span for all types of information systems in terms of the economic cost and generalizes the optimal life span. The ultimate purpose of this study is to develop a model that could be used in anticipating the timing of economic replacement of the information system of the same type and making decisions on IT investment.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.3
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• pp.165-173
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• 2007

A space launch vehicle system represents a typical example of large-scale multi-disciplinary systems, consisting of subsystems such as mechanical structure, electronics, control, telecommunication, propulsion, material engineering etc. A lot of cost is required to develop the launch vehicle system. A precise planning of R&D cost is very essential to make a success of the launch vehicle development program. Especially in the early development phase of a new space launch vehicle system, cost estimation techniques and analogy from past similar development data are very useful methods to estimate a development cost of the launch vehicle system. Now Korea Aerospace Research Institute is in charge of the KSLV-I (Korea Space Launch Vehicle-I) Program that is a part of Korea National Space program. KSLV-I Program is a national undertaking to develop launch capabilities to deliver science satellites of a 100kg-class into a low earth orbit. It is hereafter, going to plan to develop a new korean space launch vehicle. In this paper, first the development costs of well-known launch vehicles in the world are presented to provide a reference to make a development plan of a new launch vehicle. Second this paper introduces the present status of cost estimation applications at NASA. Finally this paper presents the results from application of a TRANSCOST, a parametric cost model, to derive a cost estimate of a new launch vehicle development, as an example.