• Proceedings of the Korea Information Processing Society Conference
• /
• 2004.10a
• /
• pp.465-468
• /
• 2004

의료기기 산업은 시장규모와 생산규모에서 미국이 전 세계의 $40\%$ 이상을 차지하고 있어 국내외 모든 의료기기 제조업체에서는 미국시장진출을 목표로 꾸준히 노력하고 있는 실정이다. 그러나 의료기기는 인체에 직접 적용된다는 특성으로 인해 각 국가의 정부는 저마다 다른 엄격한 기준으로 자국내 시장진출을 규제하고 있으며 엄격한 관리제도를 유지하고 있다. 국내 최신의 전자 의료기기는 필수적으로 의료기기를 제어하기 위한 의료용 소프트웨어를 필요로 하므로 의료기기 산업의 발전은 의료용 소프트웨어 산업의 발전에 직결된다고 할 수 있다. 그러나 의료기기의 경우에는 인$\cdot$허가를 위한 제도 및 절차가 갖추어져 활용되고 있는 반면, 의료용 소프트웨어의 경우에는 적합한 평가기준이 마련되어 있지 못하여 제도 및 체계구축의 필요성이 대두되고 있다. 본 논문에서는 국제표준(ISO/IEC 12119, ISO/IEC 9126을 바탕으로 평가메트릭을 구축하여 의료용 소프트웨어의 정량적인 품질을 측정, 평가하여 품질측정의 결과를 토대로 품질을 인증하는 의료응용 소프트웨어 시험인증 지원도구를 설계 및 구현하였다.

• Computers and Concrete
• /
• v.3 no.2_3
• /
• pp.79-90
• /
• 2006

This paper describes the results of an investigation into high mass-low velocity impact behaviour of reinforced concrete beams. Tests have been conducted on fifteen 2.7 m or 1.5 m span beams under drop-weight loads. A high-speed video camera has been used at rates of up to 4,500 frames per second in order to record the crack formation, propagation, particle spallation and scabbing. In some tests the strain in the reinforcement has been recorded using "Durham" strain gauged bars, a technique developed by Scott and Marchand (2000) in which the strain gauges are embedded in the bars, so that the strains in the reinforcement can be recorded without affecting the bond between the concrete and the reinforcement. The impact force acting on the beams has been measured using a load cell placed within the impactor. A high-speed data logging system has been used to record the impact load, strains, accelerations, etc., so that time histories can be obtained. This research has led to the development of computational techniques based on combined continuum/discontinuum methods (finite/discrete element methods) to permit the simulation of impact loaded reinforced concrete beams. The implementation has been within the software package ELFEN (2004). Beams, similar to those tested, have been analysed using ELFEN a good agreement has been obtained for both the load-time histories and the crack patterns.

• Structural Engineering and Mechanics
• /
• v.39 no.2
• /
• pp.267-285
• /
• 2011

There can be a significant amount of moment redistribution in composite frames consisting of steel columns and composite beams, due to cracking, creep and shrinkage of concrete. Considerable amount of computational effort is required for taking into account these effects for large composite frames. A methodology has been presented in this paper for taking into account these effects. In the methodology that has been demonstrated for moderately high frames, neural network models are developed for rapid prediction of the inelastic moments (typically for 20 years, considering instantaneous cracking, and time effects, i.e., creep and shrinkage, in concrete) at a joint in a frame from the elastic moments (neglecting instantaneous cracking and time effects). The proposed models predict the inelastic moment ratios (ratio of elastic moment to inelastic moment) using eleven input parameters for interior joints and seven input parameters for exterior joints. The training and testing data sets are generated using a hybrid procedure developed by the authors. The neural network models have been validated for frames of different number of spans and storeys. The models drastically reduce the computational effort and predict the inelastic moments, with reasonable accuracy for practical purposes, from the elastic moments, that can be obtained from any of the readily available software.

• Earthquakes and Structures
• /
• v.6 no.5
• /
• pp.539-560
• /
• 2014

Shaking tables are devices for testing structures or structural components models with a wide range of synthetic ground motions or real recorded earthquakes. They are essential tools in earthquake engineering research since they simulate the effects of the true inertial forces on the test specimens. The destructive earthquakes that occurred at the north part of Algeria during the period of 1954-2003 resulted in an initiative from the Algerian authorities for the construction of a shaking simulator at the National Earthquake Engineering Research Center, CGS. The acceleration tracking performance and specifically the inability of the earthquake simulator to accurately replicate the input signal can be considered as the main challenge during shaking table test. The objective of this study is to validate the uni-axial sinusoidal performances curves and to assess the accuracy and fidelity in signal reproduction using the advanced adaptive control techniques incorporated into the MTS Digital controller and software of the CGS shaking table. A set of shake table tests using harmonic and earthquake acceleration records as reference/commanded signals were performed for four test configurations: bare table, 60 t rigid mass and two 20 t elastic specimens with natural frequencies of 5 Hz and 10 Hz.

• Structural Engineering and Mechanics
• /
• v.62 no.2
• /
• pp.225-236
• /
• 2017

The purpose of this work is to predict ductile fracture of structural steel under extremely low cyclic loading experienced in earthquake. A cumulative damage model is proposed on the basis of an existing damage model originally aiming to predict fracture under monotonic loading. The cumulative damage model assumes that damage does not grow when stress triaxiality is below a threshold and fracture occurs when accumulated damage reach unit. The model was implemented in ABAQUS software. The cumulative damage model parameters for steel base metal, weld metal and heat affected zone were calibrated, respectively, through testing and finite element analyses of notched coupon specimens. The damage evolution law in the notched coupon specimens under different loads was compared. Finally, in order to examine the engineering applicability of the proposed model, the fracture performance of beam-column welded joints reported by previous researches was analyzed based on the cumulative damage model. The analysis results show that the cumulative damage model is able to successfully predict the cracking location, fracture process, the crack initiation life, and the total fatigue life of the joints.

• Asia-Pacific Journal of Business
• /
• v.6 no.1
• /
• pp.27-43
• /
• 2015

The objective of the present study is to identify the security factors that influence customer trust towards intention to continue using Internet banking in Malaysia. The participants are individual Internet banking users in Peninsular Malaysia. Data was collected through self-administered questionnaires distributed using the drop-off and pick-up (DOPU) technique to bank branch managers who then passed the questionnaires to their customers. A total of 413 respondents completed the questionnaires. The SPSS statistical analysis software package and Partial Least Squares statistical method were used for data analysis and hypothesis testing. The results show that authentication, confidentiality, data integrity and non-repudiation are significant factors that influence customer trust towards intention to continue using Internet banking. Trust plays a critical role in influencing the intention to continue using Internet banking in Malaysia while perceived privacy does not. An understanding of the factors identified in this study will enable Internet banking providers to effectively and efficiently enhance the security of services and thereby promote continued usage of Internet banking among customers. The findings of this study are thus expected to be of great use to Internet banking providers as improvements in Internet banking security will increase business in the long run.

• Journal of Magnetics
• /
• v.22 no.1
• /
• pp.34-42
• /
• 2017

Material defects in the Steam Generator Tubes (SGT) of sodium cooled fast breeder reactor (PFBR) can lead to leakage of water into sodium. The water and sodium reaction will lead to major accidents. Therefore, the examination of steam generator tubes for the early detection of defects is an important requirement for safety and economic considerations. In this work, the Magnetic Flux Leakage (MFL) based Non Destructive Testing (NDT) technique is used to perform the defect detection process. The rectangular notch defects on the outer surface of steam generator tubes are modeled using COMSOL multiphysics 4.3a software. The obtained MFL images are de-noised to improve the integrity of flaw related information. Grey Level Co-occurrence Matrix (GLCM) features are extracted from MFL images and taken as input parameter to train the neural network. A comparative study on characterization have been carried out using feed-forward back propagation (FFBP) and cascade-forward back propagation (CFBP) algorithms. The results of both algorithms are evaluated with Mean Square Error (MSE) as a prediction performance measure. The average percentage error for length, depth and width are also computed. The result shows that the feed-forward back propagation network model performs better in characterizing the defects.

• Structural Engineering and Mechanics
• /
• v.12 no.5
• /
• pp.541-558
• /
• 2001

The design specifications of guard fences in Japan were reexamined and the revised specifications were implemented from April 1999. Because of the huge consumption in time and cost to test the performances of full-scale guard fences in the field, some assumptions are adopted while modifying the design specifications, and numerical analyses are necessary to confirm the impact performance and safety level of new types of steel highway guard fences. In this study, the finite element models are developed for the heavy trucks and steel highway guard fences to reenact their behaviors, and the solution approach is carried out using nonlinear dynamic analysis software of structures in three dimensions (LS-DYNA). The numerical simulation results are compared with the full-scale on-site testing results to verify the proposed analysis procedure. The collision process is simulated and it is also made possible to visualize the movement of the truck and the performances of guard fences. In addition, the energy shift of the truck kinetic energy to the truck and guard fence Internal energy, and the energy absorption of each guard fence component are studied for the development of a new design methodology of steel highway guard fences based on the energy absorption capacity.

• International Journal of Railway
• /
• v.2 no.3
• /
• pp.99-106
• /
• 2009

Checks and tests before putting safety facilities into service as well as the results of these tests are essential, time consuming and may show great variations between each other. Economic constraints and the increasing complexity associated with the development of computerized tools tend to limit the capacity of the classic approval process (manual or automatic). A reduction of the validation cover rate could result in practice. This is not compatible with the French national plan to renew the interlocking systems of the national network. The method and the tool presented in this paper makes it possible to formally validate new computerized systems or evolutions of existing French interlocking systems with real-time functional interpreted Petri nets. The aim of our project is to provide SNCF with a method for the formal validation of French interlocking systems. A formal proof method by assertion, which is applicable to industrial automation equipment such as interlocking systems, and which covers equally the specification and its real software implementation, is presented in this paper. With the proposed method we completely verify that the system follows all safety properties at all times and does not show superfluous conditions: it replaces all the indoor checks (not the outdoor checks). The advantages expected are a significant reduction of testing time and of the related costs, an increase of the test coverage rate, an answer to the new demand of railway infrastructure maintenance engineering to modify and validate computerized interlocking systems. Formal methods mastery by infrastructure engineers are surely a key to prove that more safety is not necessarily more expensive.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.1
• /
• pp.30-37
• /
• 2018

Unlike an AC system, a DC system does not cause problems with synchronization, stability, reactive power, system losses, and cost. However, more research is still required for the application of DC Systems. This paper proposes a stable black-start strategy for a stand-alone DC micro-grid, which consists of an energy storage system, photovoltaic generator, wind-turbine generator, diesel generator, and DC loads. The proposed method is very important for avoiding inrush current and transient overvoltage in the power system equipment during restoration after a blackout. PSCAD/EMTDC software was used to simulate, analyze, and verify the method, which was found to be stable and applicable for a stand-alone DC micro-grid.