• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.1
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• pp.79-87
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• 2008

Seismic performance evaluation of structure requires an estimation of the structural performance in terms of displacement demand imposed by earthquakes on the structure. Incremental Dynamic Analysis(IDA) is a analysis method that has recently emerged to estimate structural performance under earthquakes. This method can obtained the entire range of structural performance from the linear elastic stage to yielding and finally collapse by subjecting the structure to increasing levels of ground acceleration. Most structures are expected to deform beyond the limit of linearly elastic behavior when subjected to strong ground motion. The nonlinear response history analysis(NRHA) among various nonlinear analysis methods is the most accurate to compute seismic performance of structures, but it is time-consuming and necessitate more efforts. The nonlinear approximate methods, which is more practical and reliable tools for predicting seismic behavior of structures, are extensively studied. The uncoupled modal response history analysis(UMRHA) is a method which can find the nonlinear reponse of the structures for ESDF from the pushover curve using NRHA or response spectrum. The direct spectrum analysis(DSA) is approximate nonlinear method to evaluate nonlinear response of structures, without iterative computations, given by the structural linear vibration period and yield strength from the pushover analysis. In this study, the practicality and the reliability of seismic performance of approximate nonlinear methods for incremental dynamic analysis of mixed building structures are to be compared.

• Journal of Korean Society of Steel Construction
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• v.13 no.5
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• pp.477-492
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• 2001

About half of bridges in United States are considered to be deficient and therefore are in need of repair or replacement. Half of these are functionally obsolete, and others do not have required strength For these bridges repairs and replacements are needed To avoid the high cost of rehabilitation the bridge rating must corectly report the present load-carrying capacity Rating engineers use Allowable Stress Design(ASD) Load Factor Design(LFD), and Load Resistance Factor Design(LRFD) to evaluate the bridge load carrying capacity In this paper the load rating methods are introduced and bridge load test data are collected. The reasons that make the difference between test results and analytical results are explained for each bridge load test And load rating methods are applied to real bridge. The rating factors from each method are compared.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.1161-1167
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• 2006

본 논문에서는 구조, 행위, 리소스, 환경의 여러 관점을 적용한 다양한 모델들을 이용하는 적응 프레임워크를 제안한다. 또한, 대상 시스템에 대해 앞에서 언급한 4 가지 모델을 위한 모델링 방법론과 각 모델링 요소들에 대한 효과적인 표기법을 제시하였다. 다양한 모델들을 통해 시스템의 구성 요소들 간의 관계 구조와 시스템의 계층적 상태와 행위 정보, 실행 환경을 구성하는 시스템 의존적인 요소 및 독립적인 요소까지의 정보들이 표현된다. 이들 모델간의 유기적인 상호 운용으로 통합적인 추론과 보다 정확한 평가가 가능하다. 이를 통해 시스템은 예상치 못한 변화에 대해 통합된 관점의 더욱 정확한 진단과 반영할 수 있다. 이를 기반으로 다양한 수준에서 적응 동작의 조절을 수행함으로써 하이브리드하고 보다 확장된 적응이 가능해진다. 논문에서 정의한 모델과 제안 프레임워크는 다른 도메인으로 재사용이 가능하다. 제안 시스템은 평가를 위해 프로토타입을 구현하여 원격 화상 회의 시스템에 적용하였으며, 그 기능과 유효성을 확인하였다.

• Journal of Genetic Medicine
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• v.8 no.1
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• pp.28-34
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• 2011

Most clinicians understand clinical trials as the evaluation process for new medicine before their use. However, clinical trials can also be applied to laboratory diagnostic tests (LDTs) to verify diagnostic accuracy and efficacy before their clinical laboratory implementation for patients. The clinical trial of LDT has two distinctive characteristics that are different from the case of pharmaceuticals and thus worth special consideration. One of them is the level of evidence. The well-designed randomized controlled trials (RCTs) are known to provide the best evidence to prove the clinical efficacy of any pharmaceutical products. However, RCTs lose practicality when applied to LDTs due to various issues including ethical complications. For this reason, comparative study format is considered more feasible approach for LDTs. In addition pharmaceuticals and LDTs are different in that the user's intervention is not required for the former but critical to the latter. Moreover, in the case of pharmaceuticals, end-products are produced by manufacturers before being used by clinicians. However, in LDTs, once reagents and instruments are provided by manufacturers, they are first utilized by clinical laboratories to produce test results in order for clinicians to use them later. In other words, when it comes to LDTs, clinical laboratories play the role of manufacturers, providing reliable test results with improved quality assurance. Considering the distinctive characteristics of LDTs, we would like to offer detailed suggestions to successfully perform clinical trials in LDTs, which include analytical performance measures, clinical test performance measures, diagnostic test accuracy measures, clinical effectiveness measures, and post-implementation surveillance.

• Geotechnical Engineering
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• v.12 no.6
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• pp.87-100
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• 1996

This paper verifies the accuracy and efficiency of the implicit stress integration algorithm for an anisotropic hardening constitutive model developed in a companion paper[Oh & Lee (1996)3. Simulation of undrained triaxial test results shows the accuracy of the method through an error estimation, and analyses of accuracy and convergence were performed for a numerical excavation problem. As a result, the stress was accurately integrated by the algorithm and the nonlinear solution was converged to be asymptotically quadratic. Furthermore nonlinear FE analysis of a real excavation problem was by performed considering the initial soil conditions and the in-situ construction sequences. The displacements of wall induced by excavation were more accurately estimated by the anisotropic hardening model than by the Cam-clay model.

• Geotechnical Engineering
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• v.14 no.4
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• pp.129-140
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• 1998

Elasto-plastic finite element analysis of geotechnical boundary value problems necessitate the stress integration for the known strain increments. For the elasto-plastic constitutive model, the stress integration is generally achieved by numerical schemes, because analytical integration is impossible for general strain path. In this case, the accuracy of numerical stress integration has an important role on the overall accuracy of nonlinear finite element solution. In this study, the Sloan's substepping method which is one of explicit integration methods has been adopted and iris applicability has been checked. The unstability and inaccuracy of ifs results initiated from initial stress level were revealed. So. a new modified numerical integration method which employs the basic concept of modified Euler scheme for error control is proposed and accuracy and stability of the solutions are confirmed by triaxial test simulation.

• 사료
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• s.63
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• pp.70-76
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• 2013

사료에 있어서 가장 중요한 영양소 중에 하나는 단백질이다. 단백질은 가축의 성장, 유지, 생산근육, 효소, 호르몬, 우유, 털 등)에 필수적인 영양소이다. 가축의 단백질 요구량은 가축의 성장단계, 개체크기, 유전적인 능력 등에 따라 달라진다. 그러므로 가축에게 공급되는 단백질의 양은 정확하게 평가되어야한다. 너무 과도한 단백질 공급은 동물이 불필요한 에너지를 생산하게 만들고 너무 적은 단백질 공급은 아미노산 결핍이 일어나게 할 수 있다. 가축이 요구하는 정확한 양의 단백질을 공급하는 것이 중요하고 이를 위해서는 사료내 단백질의 양을 정확하게 분석하는 것이 선행되어야 한다. 사료에 있어 단백질 함량은 사료 내 질소의 양을 정량해서 간접적으로 환산하고 추정한 조단백질(Crude Protein)로 표현한다. 샘플내의 질소가 모두 아미노산에서 온 것이라고 가정하고, 단백질이 평균적으로 16%의 질소를 가지고 있기 때문에 (1/0.16=6.25) 정량한 질소수치에 단백질 환산 계수 6.25를 곱해서 표현한다. 그러나 사료원료마다 아미노산 조성이 다르기 때문에 사료원료마다 다른 단백질 환산 계수를 사용해야 한다는 주장도 있다. 단백질 환산 계수에 관한 리뷰논문을 보면 대두의 경우 5.71에5서부터 유제품의 경우 6.38에 이르기까지 다양하다. 그러나 논란의 여지가 있기 때문에 이렇게 매트릭스마다 다른 단백질 환산 계수를 사용할 경우 계산식 옆에 사용한 환산계수를 적어 주어야 한다. 사료 내 조단백질을 정량하는 방법은 켈달법(Kjeldahl method), 듀마스법(combustion method), 근적외선분광분석법(NIR, Near Infrared) 등이 있는데 여기서는 주로 사료분석기관과 사료업계에서 조단백질 분석에 많이 사용하고 있는 켈달법과 듀마스법을 비교해 보고자 한다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.531-538
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• 2011

To ensure the structural integrity of membrane type LNG tank, the rational assessment of impact pressure and structural responses due to sloshing should be preceded. The sloshing impact pressures acting on the insulation system of LNG tank are typical irregular loads and the structural responses caused by them also very complex behaviors including fluid structure interaction. So it is not easy to estimate them accurately and huge time consuming process would be necessary. In this research, a simplified method to analyze the dynamic structural responses of LNG tank insulation system under pressure time histories obtained by sloshing model test or numerical analysis was proposed. This technique basically based on the concept of linear combination of the triangular response functions which are obtained by the transient response analysis under the unit triangular impact pressure acting on structures in time domain. The validity of suggested method was verified through the example calculations and applied to the structural analysis of real Mark III type insulation system using the sloshing impact pressure time histories obtained by model test.

• The Journal of the Korean bone and joint tumor society
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• v.11 no.1
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• pp.32-39
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• 2005

Introduction: Currently, F-18 fluorodeoxyglucose positron emission tomography scans (FDG-PET) has been investigated in soft tissue tumor especially for tumor detection and noninvasive grading. However, the validity and the efficacy of FDG-PET are still unclear in clinical evaluation. The purpose of this study is to determine the efficacy of FDG-PET in compared to conventional diagnostic imaging studies currently used in the soft tissue tumor. Methods: Between March 2001 and March 2002, 29 patients (sixteen males, thirteen females, mean age, 47 years; a range from 4 to 73) diagnosed with soft tissue tumor were evaluated by both conventional diagnostic imaging and FDG-PET. Valid reference test of the local lesion was the histopathologic diagnosis, which was measured in all patients. The suspecting metastasis in the imaging studies was validated by pathology or follow up imaging for at least 6 months. Each imaging diagnosis was made independently. The accuracy of each diagnostic method was evaluated. The incremental cost accuracy ratio was determined in each diagnostic method. Results: For detection of local lesion, sensitivity, specificity, and accuracy for MRI and FDGPET scans were 91%, 57%, 83% and 95%, 43%, 83% respectively. For detection of distant lesion, sensitivity, specificity, accuracy for conventional diagnostic methods and FDG-PET scans were 77%, 89%, 87% and 92%, 94%, 93% respectively. The incremental cost accuracy ratio (ICAR) of FDG-PET for detection of distant lesion was 145,000won/%. According to ICAR for each tumor grade, PET strategy is most cost-effective at high grade tumors. Conclusions: For detection of local lesion such as recurrence or remnant tumor, FDG-PET scan was not more accurate than MRI. However, It was more accurate for detection of metastatic lesion than conventional methods. For detection of high grade tumor, PET was most costeffective than for detection of lower grade tumor.

• Journal of Korea Technology Innovation Society
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• v.15 no.2
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• pp.262-276
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• 2012

Transactions activation of intangible assets has become became a key factor for corporate survival and successful business in the knowledge economy. Thus, demand in correctly valuating technology has increased. The market approach is the reliable method because of the premise that the market value of an asset is directly related to the prices of comparable, competitive ones. However, it can be practically impossible in many cases because it is hard to find identical transactions, which are generally closely guarded business secrets. As a result, most of technology valuation is conducted by the income approach and this approach is used to derive estimates for such unobserved variables. In September 2011, the Ministry of Knowledge Economy enacted a law for operational guideline standards for technology valuation to encourage the domestic technology valuation market. The enforcement recommended that the market approach have precedence over other approaches. If this approach cannot be applied, then the valuator should writing that he used other approaches. In practice, it is hard to know whether or not information about comparable transactions exists. The proposed process provides valuators to assess suitability for practical use of market approach through the observation process of technology transactions information. At the same time, it offers them the opportunity to gain validity when using other approaches.