• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.4
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• pp.296-304
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• 2000

Radar is becoming a popular tool for condition assessment of concrete structures. The advancement of radar method to concrete structures requires a systematic approach, which incorporates the fundamentals of radar theory and the characteristics of concrete as a material with electromagnetic properties. The research work presented in this paper deals with the establishment of effective measurement area for radar measurements, the determination of concrete thickness using radar, and the calculation of the dielectric constant of concrete from radar measurements. As results, formulas have been suggested to determine optimum measurement area for concrete, using radar and concrete thickness has been successfully identified for specimens used in this work. In the experiments, five concrete specimens which have the dimensions of 900mm (length) $\times$ 600mm (width) with thickness variation from 50mm to 250mm are used.

• Journal of Korean Society of Steel Construction
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• v.29 no.1
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• pp.61-71
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• 2017

The flexural behavior of composite ring stiffened by GFRP and steel pipe is presented in this paper. The effective width is required to construct FEM beam element model to verify the composite flexural behavior of stiffened ring of cylindrical shell structure. The experimental results are compared with the theoretical and FEM results by commercial program ABAQUS to verify the effective width coefficient. The yield, crack and ultimate loads is calculated using theoretical strains that varies depending on yield state and compared with experiment result and FEM results by ABAQUS solid model.

• Journal of the Korean Magnetics Society
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• v.4 no.2
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• pp.100-105
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• 1994

Ni-Fe thin films are deposited on the corning glass substrate by means of RF magnetron sputtering system In order to investigate the dependence of the prorerties of Ni-Fe thin films on the film thickness, ferromagnetic reson¬ance spectrum has been examined. The effective magnetization $M_{eff}$ is constant for all samples, while the exchange stiffness constant A increases with the film thickness. A tendency that spectroscopic splitting factor g increases with the sample thickness, we expect that the increase of the contribution of the orbital motion to the magnetic moment as a reason for it.

• Progress in Medical Physics
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• v.15 no.3
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• pp.167-172
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• 2004

A Siemens HD-270 MLC$^{TM}$, a virtual-micro MLC, allows to the application of a smooth field edge method due to the finite leaf-width of MLC. This technique was implemented into a Pinnacle planning system in order to evaluate the dose distributions during the planning stage. The necessary dosimetric aspects, such as undulation and effective penumbra, were investigated with variations in the resolutions of a virtual-micro MLC and field edge angle. The positional accuracy of the couch movement was also assessed for clinical implementation. The overhead time for planning and treatment was confirmed as negligible.e.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.2
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• pp.8-13
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• 1999

In this paper, an analytical threshold voltage model is proposed by replacing the conventional GCA(Gradual Channel Approximation) with the assumption that a normal depletion layer width in the intrinsic region will vary quasi-linearly according to the channel direction. Derived threshold voltage expression is written as a function of the effective channel length, drain voltage, substrate bias voltage, substrate doping concentration, and the oxide thickness. Calculated results show almost similar trends with BSIM3v3's results in a satisfactory accuracy.

• Journal of Korean Association for Spatial Structures
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• v.3 no.2 s.8
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• pp.69-75
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• 2003

In case of rectangular lattice dome which shearing rigidity is very small, it has a concern to drop Buckling strength considerably by external force. So, by means of system to increase buckling-strength, there is a method of construction that lattice of dome is one with roof material. In a case like this, shearing rigidity of roof material increases buckling-strength of the whole of structure and can be designed economically from the viewpoint of practice. In case of analysis is achieved considering roof material that adheres to lattice of dame, there is method that considers the rigidity that use effective width frame as method to evaluate rigidity of roof material. therefore, this study is aimed at deciding effective width of roof material united with rectangular lattice dome to evaluate rigidity of roof material by effective width of frame and investigating how much does rigidity of roof material united with lattice of dome increase buckling-strength of the whole of structure according to rise-ratio. Conditions of loading are vertical-type-uniform loading. Analysis method is based on FEM dealing with the geometrically nonlinear deflection problems.

• KDI Journal of Economic Policy
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• v.10 no.2
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• pp.3-26
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• 1988

본(本) 연구(硏究)의 목적(目的)은 우리나라의 1963~86년도 자료를 사용하여 소비(消費) 및 가계저축함수(家計貯蓄函數)를 추정함으로써 가계(家計), 기업(企業), 정부저축(政府貯蓄) 등 세 부문의 저축(貯蓄) 사이에 어떠한 관계, 즉 어느 정도의 대체관계(代替關係)가 있는가를 판별하고 정부저축(政府貯蓄)과 정부재정지출(政府財政支出) 등의 변수(變數)로 표시되는 재정정책(財政政策)의 구축효과(驅逐效果)와 이에 따른 재정정책(財政政策)의 유효성(有效性) 혹은 무력성(無力性) 문제(問題)를 분석하고자 함에 있다. 본(本) 연구(硏究)의 분석결과에 의하면 기업저축(企業貯蓄)과 정부저축(政府貯蓄)은 가계저축(家計貯蓄)과 대체관계(代替關係)가 아닌 보완관계(補完關係)를 갖는 것으로 나타난다. 이는 일국전체(一國全體)의 자본형성(資本形成)에 있어서 기업(企業) 및 정부저축(政府貯蓄)이 매우 중요한 정책변수(政策變數)임을 시사하는 것으로 가계저축율(家計貯蓄率), 나아가 국내저축율(國內貯蓄率)의 제고(提高) 및 유지(維持)를 위해 기업저축증대(企業貯蓄增大)를 위한 제반유인정책(諸般誘因政策)을 꾸준히 강화하고 정부저축증대(政府貯蓄增大)를 위한 효율적이고 건전한 재정운용(財政運用)이 지속되어야 할 것이다. 한편 정부재정지출(政府財政支出)은 적자(赤字)에 의하는 조세(租稅)에 의하든 민간소비(民間消費)를 큰 폭으로 증가시키는 것으로 나타나 가계(家計)의 초합리성가설(初合理性假說)이나 완전(完全)한 선견가설(先見假說)이 상정하는 바와 같이 재정정책(財政政策)의 완전(完全)한 구축효과(驅逐效果)가 나타남에 따른 재정정책(財政政策)의 무력성(無力性) 결과(結果)와 대조적으로 우리나라의 재정정책(財政政策)이 그동안 경제안정(經濟安定)을 위한 강력한 정책수단(政策手段)으로서의 역할을 수행해 왔음을 보여주고 있다.

• Korean Journal of Crystallography
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• v.14 no.1
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• pp.16-23
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• 2003

The electronic structure and chemical bonding of β-MnO₂ were theoretically investigated by DV-X/sub α/ (the discrete variation X/sub α/) method. which is a sort of the first principle molecular orbital method using Hatre-Fock-Slater approximation. The calculations on several cluster models having different sizes were carried out for the determination of a model suited for analyzing bulk state. The Mn/sub 15/O/sub 56/ model was selected as a sufficiently suitable model for the calculation of electronic state and chemical bonding by the comparison of the calculated XPS (X-ray photo-electron spectrum) and experimentally measured XPS. By using this model, the electron energy level, the density of state, the bond overlap population, the charge density distribution, and the net ionic transfer between cations and anions were calculated and discussed.

• Journal of Convergence for Information Technology
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• v.11 no.11
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• pp.17-22
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• 2021

Radar signal analysis of electronic warfare is a technique for identifying a radar type by signal parameters(direction, radion frequency, pulse repetition interval, pulse width, scan period..) extracted from a received radar pulse. However as the modern radar and new threat environments is advanced, radar identification ambiguity arises in the process of identifying the types of radars. In this paper, we analyze the problems of the existing method and propose a new method. This technique determines the validity of the scan period by the difference in the arrival time of the radar pulse and the minimum number of scan period discrimination. Experiments proved that the scan cycle results are derived regardless of the RMS((Root Mean Square) of the input amplitude.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.98-105
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• 2018

Cracks in RC members occurred as a result of material and structural factors. The crack width and a crack location are very difficult to examine. A direct crack control method and indirect crack control method to control a crack are presented in the KHBDC (LSD) and KSCDC (2012). In the KSCDC text, cracks are controlled by steel spacing indirectly under a service load. On the other hand, in the KSCDC appendix, cracks are controlled by a crack width directly under a sustained load. In particular, the loading state considered is different. On the other hand, cracks are controlled under a combination of service load and an effective elastic modulus is used in KHBDC. Therefore, in this study, an effective elastic modulus that can reflect the ratio of the sustained load and live load was applied, and a maximum steel spacing was calculated through a design crack width. A variable interpretation was carried out, and a rational crack control method was assessed. As a result, a steel spacing through the design crack width in the KSCDC was smaller than that from the design crack width in the KHBDC, which leads to a conservative design. In addition, the maximum steel spacing suggested in this study has a consistency eliminating the difference between direct crack control and indirect crack control.