• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권6호
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• pp.1869-1880
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• 2014

Wireless communication is one of most active areas in modern communication researches, QoS (Quality of Service) assurance is very important for wireless communication systems design, especially for applications such as streaming video etc., which requires strict QoS assurance. The modern wireless networks multi-layer protocol stack structure results in QoS metrics layered and acting in cascade and QoS metrics vertical mapping between protocol layers. Based on virtual buffer between protocol layers and queuing technology, a unified layered QoS mapping framework is proposed in this paper, in which we first propose virtual queue concept, give a novelty united neighboring protocol layers QoS metric mapping framework, and analysis method based on dicerete-time Markov chain, and numerical results show that our proposed framework represents a significant improvement over previous model.

• 한국정밀공학회지
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• 제23권3호
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• pp.187-194
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• 2006

Unexpected postoperative changes, such as growth in rib hump and shoulder unbalance, have been occasionally reported after corrective surgery for scoliosis. However there has been neither experimental data fer explanation of these changes, nor the suggestion of optimal correction method. Therefore, the numerical study was designed to investigate the post-operative changes of vertebral rotation and rib cage deformation after the corrective surgery of scoliosis. A mathematical finite element model of normal spine including rib cage, sternum, both clavicles, and pelvis was developed with anatomical details. In this study, we also developed a special program which could convert a normal spine model to a desired scoliotic spine model automatically. A personalized skeletal deformity of scoliosis model was reconstructed with X-ray images of a scoliosis patient from the normal spine structures and rib cage model. The geometric mapping was performed by translating and rotating the spinal column with an amount analyzed from the digitized 12 built-in coordinate axes in each vertebral image. By utilizing this program, problems generated in mapping procedure such as facet joint overlapping, vertebral body deformity could be automatically resolved.

• Geomechanics and Engineering
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• 제11권3호
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• pp.325-343
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• 2016

A total stress-based bounding surface model is developed to predict the undrained behaviour of saturated soft clays under cyclic loads based on the anisotropic hardening modulus field and bounding-surface theories. A new hardening rule is developed based on a new interpolation function of the hardening modulus that has simple mathematic expression and fewer model parameters. The evolution of hardening modulus field is described in the deviatoric stress space. It is assumed that the stress reverse points are the mapping centre points and the mapping centre moves with the variation of loading and unloading paths to describe the cyclic stress-strain hysteresis curve. In addition, by introducing a model parameter that reflects the accumulation rate and level of shear strain to the interpolation function, the cyclic shakedown and failure behaviour of soil elements with different combinations of initial and cyclic stresses can be captured. The methods to determine the model parameters using cyclic triaxial compression tests are also studied. Finally, the cyclic triaxial extension and torsional shear tests are performed. By comparing the predictions with the test results, the model can be used to describe undrained cyclic stress-strain responses of elements with different stress states for the tested clays.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.217-220
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• 2005

Currently, a number of control points are required in order to achieve accurate geolocation of satellite images. Control points can be generated from existing maps or surveying, or, preferably, from GPS measurements. The requirement of control points increase the cost of satellite mapping, let alone it makes the mapping over inaccessible areas troublesome. This paper investigates the possibilities of modeling an entire imaging strip with control points obtained from a small portion of the strip. We tested physical sensor models that were based on satellite orbit and attitude angles. It was anticipated that orbit modeling needed a sensor model with good accuracy of exterior orientation estimation, rather then the accuracy of bundle adjustment. We implemented sensor models with various parameter sets and checked their accuracy when applied to the scenes on the same orbital strip together with the bundle adjustment accuracy and the accuracy of estimated exterior orientation parameters. Results showed that although the models with good bundle adjustments accuracy did not always good orbit modeling and that the models with simple unknowns could be used for orbit modeling.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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• pp.86-93
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• 2002

A new error estimation method is proposed. This utilizes the variation of energy functional about the mapping function between the global and the master elements. The resultant system of equations is the weak form of the generalized conservation checks. However, This formulation has an important information about the relations between the connected elements. In other words, some relations between the connected elements are obtained and these can be used very usefully to measure it posteriori error. In this paper, the explicit formulations are presented for the 1-dimensional model and the 2-dimensional model problems. Numerical results are provided for first order shear deformation theody of beam model and the plane stress problem.

• Journal of electromagnetic engineering and science
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• 제11권3호
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• pp.192-200
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• 2011

This paper proposes a new modeling method for estimating the impedance of an on-chip power/ground meshed plane. Frequency dependent R, L, and C parameters are extracted based on the proposed method so that the model can be applied from DC to high frequencies. The meshed plane model is composed of two parts: coplanar multi strip (CMS) and conductor-backed CMS. The conformal mapping technique and the scaled conductivity concept are used for accurate modeling of the CMS. The developed microstrip approach is applied to model the conductor-backed CMS. The proposed modeling method has been successfully verified by comparing the impedance of RLC circuit based on extracted parameters and the simulated impedance using a 3D-field solver.

• 대한원격탐사학회지
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• 제18권5호
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• pp.273-280
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• 2002

This paper describes a mathematical model and its utilization algorithm for calculating the accurate target position on the ellipsoidal earth surface which corresponds to a range-azimuth coordinates of unprocessed synthetic aperture radar (SAR) images. A geometrical model which is a set of coordinate transformations is described. The side-looking directional angle (off-nadir angle) is determined in an iterative fashion by using the model and the accurate slant range which is calculated from the range sampling timing of the instrument. The algorithm can be applied not only for the geolocation of SAR images but also for the high quality SAR image generation by calculating accurate Doppler parameters.

• 소음진동
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• 제10권3호
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• pp.410-422
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• 2000

This paper proposes a model of standardized noise map in korea, The standardization of noise map is accomplished by standardizing the way of map description and by applying international noise mapping criteria to Korean environment. The proposed model can be an useful star or the production of national standardized noise map in Korea.

• 한국측량학회지
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• 제19권1호
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• pp.19-26
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• 2001

기술적인 프로젝트를 수행하는 기관들은 전문가들의 도움을 받는 것이 보편화되어가고 있다. 프로젝트를 사전 검토하는 전문가들은 정보화 기술과 측량 및 매핑의 변화된 기술과 함께 경제적인 방법에 대한 분야에 대한 전문적인 지식이 있어야 한다. 토털스테이션, GPS, 정사사진, 수치지도 및 위성 리모트센싱과 같은 새로운 측량 및 매핑 방법은 과거의 측량 개념을 송두리째 바꾸어버렸다. 또한 매핑에 대한 기술은 지난 50년 동안 기계식에서 해석적 그리고 수치적으로 크게 변화되었다. 이제 측량 및 매핑 방법들의 적절한 선택은 특정한 기술의 사용보다는 비용과 효과 측면에서의 결정사항이 되고 있다. 예를 들어 GPS측량기는 종래의 측량기기보다 더 비싸지만 비용효율적인 측면에서 장점을 제공하고 있다. 본 연구에서는 측량 및 매핑 프로젝트에서의 비용인자와 효과인자를 독립적으로 평가하였고, 비용/효과 비(B/C비)를 평가모델에 사용하여 각 측량방법의 비용 효과를 비교하였다. 측량 및 매핑 방법들의 비용 대 효과 모델은 전체 프로젝트에서 경제적인 결과를 얻을 수 있을 것이다.

• 한국인터넷방송통신학회논문지
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• 제11권2호
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• pp.127-133
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• 2011

본 논문에서는 고속 스위칭이 가능한 멀티 프로토콜 레벨 스위칭망에서의 DiffServ와의 서비스 결합을 위한 PHB 매핑모델을 제안 하였고, 제안된 매핑모델을 기반으로 멀티 프로토콜 레벨 스위칭망에서 대역폭을 보장하는 차등화 서비스 모델을 설계하였다. EF, BE, AF1, AF2 트래픽을 적용하여 9초 동안의 Throughput에 대한 시뮬레이션 결과, 전체 발생된 트래픽은 2.45Mbps로 링크의 수용가능 속도인 1.5Mbps의 60%를 초과한 트래픽을 발생시켰다. AF1과 AF2는 trTCM의 PIR 값인 700Kbps 및 600Kbps로 설정되어있어 링크에서의 포화 상태의 흐름을 확인 미터링을 수행하고 trTCM을 이용하여 마킹을 적용한 후 전송률을 PIR에 적용되어 전송됨을 확인할 수 있으며, Priority의 우선순위가 BE보다 높으므로 우선적으로 전송됨을 확인 할 수 있었다. BE인 경우 우선순위가 AF1, AF2보다 낮아 링크에서의 포화 상태 발생시 기아문제가 발생됨을 알 수 있다. EF, BE, AF1, AF2 동시 전송시 BE의 트래픽 전송은 거의 기아상태에 있음을 확인 할 수 있었다. AF1 폐기율과 AF2 폐기율의 경우 AF1은 trTCM의 PIR, CIR 값이 AF2 높으며 우선순위도 높아 AF2보다 패킷 폐기율이 낮다. 그러나 BE는 링크에서의 병목현상이 발생 시 AF1, AF2에 의한 네트워크 자원의 우선으로 패킷에 대한 전송이 전혀 이루어지지 않고 있음을 알 수 있다.