• 한국지능시스템학회논문지
• /
• 제20권5호
• /
• pp.631-637
• /
• 2010

본 연구에서는 교통 신호를 능동적으로 제어하기 위하여 횡단보도영역에서 보행자의 행동을 판단하는 방법을 제안한다. 코드북기법을 이용하여 보행자 객체를 검출하고, 외곽선을 정보를 획득한다. 신속한 객체 검출을 위하여 CUDA(Compute Unified Device Architecture)기반 병렬화 처리한다. 해당 객체의 형상정보에 왜곡을 일으키는 투영 음영을 제거한 후, 보행자 객체가 보행자인지 혹은 차량, 동물인지를 식별하기 위해 힐버트 스캔 거리값(Hilbert Scan Distance)을 이용한 형판정합 기법을 수행한다. 정합 후에는 보행자 객체의 움직임, 얼굴영역의 특징, 대기 시간의 분석을 통하여 보행자의 횡단보도 이용 의지를 판단하고 교통신호를 제어한다.

• 한국전산구조공학회논문집
• /
• 제17권3호
• /
• pp.319-332
• /
• 2004

복합재료(FRP)는 재료적 고비강도, 고내구성 등으로 인하여 건설분야에 널리 사용되고 있어, 본 연구에서는 인발성형된 FRP 바닥판의 형상최적설계를 수행하였다. 최적설계의 정식화에서 목적함수는 단위모듈의 체적을 최소화하도록 하였으며, 설계변수는 바닥판 단면의 기하적 치수와 재료적 물성을 사용하였다. 반면 바닥판의 성능을 최대한 효율적으로 설계하기 위하여 설계 제약조건으로 처짐규정, 재료파괴 기준, 좌굴하중, 바닥판 최소두께와 응력을 사용하였다. 단면형상의 효율적 결정과 시공성을 고려하여 구조적 보조부재를 포함하지 않는 튜브 모양의 형상으로 제한하였으며, 최적화 알고리즘은 Index기법을 적용하여 수렴성을 극대화한 개선된 GAs를 사용하였다. 상용 프로그램인 ABAQUS를 사용하여 3차원 유한요소해석을 수행하였고, 구조해석 결과를 최적화 과정에 필요한 제약조건으로 활용하고, 민감도 분석을 수행하였다. 본 연구를 통하여 개발한 최적화 프로그램을 검증하기 위하여, 40m의 지간, 폭 12.14m에 주형 간격이 2.5m인 단순교를 대상으로 하였으며, 도로교 설계 기준을 만족하는 DB-24하중을 적용하였다. 복합재료의 재료로 E-glass섬유를 사용하였으며, 최적설계를 수행한 결과 인발성형공법에 의한 실용적인 단면을 제안하였다.

• Journal of Radiation Protection and Research
• /
• 제41권3호
• /
• pp.237-244
• /
• 2016

Background: Korea Atomic Energy Research Institute is developing a fission product transport module for predicting the behavior of radioactive materials in the primary cooling system of a nuclear power plant as a separate module, which will be connected to a severe accident analysis code, Core Meltdown Progression Accident Simulation Software (COMPASS). Materials and Methods: This fission product transport (COMPASS-FP) module consists of a fission product release model, an aerosol generation model, and an aerosol transport model. In the fission product release model there are three submodels based on empirical correlations, and they are used to simulate the fission product gases release from the reactor core. In the aerosol generation model, the mass conservation law and Raoult's law are applied to the mixture of vapors and droplets of the fission products in a specified control volume to find the generation of the aerosol droplet. In the aerosol transport model, empirical correlations available from the open literature are used to simulate the aerosol removal processes owing to the gravitational settling, inertia impaction, diffusiophoresis, and thermophoresis. Results and Discussion: The COMPASS-FP module was validated against Aerosol Behavior Code Validation and Evaluation (ABCOVE-5) test performed by Hanford Engineering Development Laboratory for comparing the prediction and test data. The comparison results assuming a non-spherical aerosol shape for the suspended aerosol mass concentration showed a good agreement with an error range of about ${\pm}6%$. Conclusion: It was found that the COMPASS-FP module produced the reasonable results of the fission product gases release, the aerosol generation, and the gravitational settling in the aerosol removal processes for ABCOVE-5. However, more validation for other aerosol removal models needs to be performed.

• Structural Engineering and Mechanics
• /
• 제8권2호
• /
• pp.165-180
• /
• 1999

The cost effectiveness of using steel roof systems for residential buildings is becoming increasingly apparent with the decrease in manufacturing cost of steel components, reliability and efficiency in construction practices, and the economic and environmental concerns. While steel has been one of the primary materials for structural systems, it is only recently that its use for residential buildings is being explored. A comprehensive system for the design of residential steel roof truss systems is presented. In the first stage of the research the design curves obtained from the AISI-LRFD code for the manufactured cross-sections were verified experimentally. Components of the truss systems were tested in order to determine their member properties when subjected to axial force and bending moments. In addition, the experiments were simulated using finite element analysis to provide an additional source of verification. The second stage of the research involved the development of an integrated design approach that would automatically design a lowest cost roof truss given minimal input. A modified genetic algorithm was used to handle sizing, shape and topology variables in the design problem. The developed methodology was implemented in a software system for the purpose of designing the lowest cost truss that would meet the AISI code provisions and construction requirements given the input parameters. The third stage of the research involved full-scale testing of a typical residential steel roof designed using the developed software system. The full scale testing established the factor of safety while validating the analysis and design procedures. Evaluation of the test results indicates that designs using the present approach provide a structure with enough reserve strength to perform as predicted and are very economical.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제13권2호
• /
• pp.962-977
• /
• 2019

The human voice is a convenient method of information transfer between different objects such as between men, men and machine, between machines. The development of information and communication technology, the voice has been able to transfer farther than before. The way to communicate, it is to convert the voice to another form, transmit it, and then reconvert it back to sound. In such a communication process, a vocoder is a method of converting and re-converting a voice and sound. The CELP (Code-Excited Linear Prediction) type vocoder, one of the voice codecs, is adapted as a standard codec since it provides high quality sound even though its transmission speed is relatively low. The EVRC (Enhanced Variable Rate CODEC) and QCELP (Qualcomm Code-Excited Linear Prediction), variable bit rate vocoders, are used for mobile phones in 3G environment. For the real-time implementation of a vocoder, the reduction of sound quality is a typical problem. To improve the sound quality, that is important to know the size and shape of noise. In the existing sound quality improvement method, the voice activated is detected or used, or statistical methods are used by the large mount of data. However, there is a disadvantage in that no noise can be detected, when there is a continuous signal or when a change in noise is large.This paper focused on finding a better way to decrease the reduction of sound quality in lower bit transmission environments. Based on simulation results, this study proposed a preprocessor application that estimates the SNR (Signal to Noise Ratio) using the spectral SNR estimation method. The SNR estimation method adopted the IMBE (Improved Multi-Band Excitation) instead of using the SNR, which is a continuous speech signal. Finally, this application improves the quality of the vocoder by enhancing sound quality adaptively.

• Geomechanics and Engineering
• /
• 제36권4호
• /
• pp.355-366
• /
• 2024

The original elastoplastic Hardening Soil model is formulated actually partly under hexagonal pyramidal Mohr-Coulomb failure criterion, and can be only used in specific stress paths. It must be completely generalized under Mohr-Coulomb criterion before its usage in engineering practice. A set of generalized constitutive equations under this criterion, including shear and volumetric yield surfaces and hardening laws, is proposed for Hardening Soil model in principal stress space. On the other hand, a Mohr-Coulumb type yield surface in principal stress space comprises six corners and an apex that make singularity for the normal integration approach of constitutive equations. With respect to the isotropic nature of the material, a technique for processing these singularities by means of Koiter's rule, along with a transforming approach between both stress spaces for both stress tensor and consistent stiffness matrix based on spectral decomposition method, is introduced to provide such an approach for developing generalized Hardening Soil model in finite element analysis code ABAQUS. The implemented model is verified in comparison with the results after the original simulations of oedometer and triaxial tests by means of this model, for volumetric and shear hardenings respectively. Results from the simulation of oedometer test show similar shape of primary loading curve to the original one, while maximum vertical strain is a little overestimated for about 0.5% probably due to the selection of relationships for cap parameters. In simulation of triaxial test, the stress-strain and dilation curves are both in very good agreement with the original curves as well as test data.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2007년도 춘계학술대회 논문집
• /
• pp.149-154
• /
• 2007

The zinc prosphate film treatments used to lubricating treatment of mostly cold forging processes. But there are several problems happened to lubricating treatment process such as happening harmful environment on person, complex lubrication processing occurring in energy and time consumption, eco-destructive and chemical by-product generation, the needs of waste disposal etc. As a result, a water-soluble lubricant was developed to replace the perfect or some of the zinc prosphate film in the world. In order to solve these problems, this study evaluated the performance of the typical water-soluble. In this study, for these requirement inquiry of two part. First, about possibility of replace zinc phosphate lubricant, quantitatively evaluation developed of water-soluble lubricant for cold forging vs zinc phosphate lubricant. Second, About optimization of coating Process use to equipment with practicable automatic coating Process. The performance evaluation of these lubricants was conducted using the double cup extrusion test and spike forging test. With the use of the commercial FE code DEFORM, friction factor calibration curves, i.e. cup height ratio vs. punch stroke and spike height vs. punch stroke, were established for different friction factor values. By matching the cup height ratio and the punch stroke and spike height vs. punch stroke from experiment to that obtained from FE simulations, the friction factor of the lubricants was determined. Survey of comparative analysis use to SEM that sprayed lubricant surface structure of grain shape and characteristic of lubricant performance based on grain shape and deformed lubricant surface expansion. As a result, developed lubricant were found to perform comparable to or better than zinc phosphate. And thought this result, innovatively cope with generated problem of existing lubrication process.

• Journal of Ship and Ocean Technology
• /
• 제11권2호
• /
• pp.10-25
• /
• 2007

With the sharp increase of the oil price, the issue of the energy saving requires even higher propulsive efficiency of the propellers. Traditionally the propellers have been designed with the criteria such as that of Lerbs optimum based on the lifting line theory and the empirical formulae of Lerbs and van Manen giving relations of the wake pitch with the wake non-uniformity. With the aid of the high speed computer, it is now possible to apply the time-consuming iterative approaches for the solution of the lifting surface problems. In this paper we formulate the variational problem to optimize the efficiency of the propeller operating in the given ship wake using the lifting surface method. The variational formulation relating the spanwise circulation distribution with the propulsive efficiency to be maximized is however non-linear in circulation distribution functions, thus the iterative method is applied to the quasi-linearized equations. The blade shape design also requires the iterative procedures, because the shape of the blade which is represented by the lifting surface is unknown a priori. The numerical code was validated with the DTNSRDC propeller 4119 which is well-known to be optimum in uniform inflow condition. In addition existing (well-designed) commercial propellers were selected and compared with the results of the open water tests and the self-propulsion tests.

• 한국전산구조공학회논문집
• /
• 제20권3호
• /
• pp.393-404
• /
• 2007

본 연구에서는 교량정보의 통합 운용을 지원하기 위해 멀티레이어 데이터베이스의 프레임워크를 제시하였다. 멀티레이어 데이터베이스란 표준화된 정보 레이어로 이루어진 논리적으로 통합된 데이터베이스를 말한다. 표준화된 정보 레이어는 한 부류로 구분할 수 있는 데이터 집합을 나타내며, 정보모델에 의해 정의된다. 본 연구에서 제시한 교량의 멀티레이어 데이터베이스 개념은 구조요소의 분류를 나타내는 정보체계를 기반으로 하며, 구조요소의 분류체계에 따른 코드를 사용함으로써 여러 정보계층에 분포된 데이터를 통합하도록 하였다. 또한 멀티레이어 데이터베이스 프레임워크의 한 축으로서 데이터 레벨을 설정하였다. 데이터 레벨은 정보계층에 포함된 데이터들의 재활용성에 따른 중요도를 의미하며, 이에 따라 정보모델의 세분화되는 정도를 정의하여 방대한 양의 교량정보 데이터베이스 구축을 위한 효과적인 전략수립이 가능하도록 하였다. 제시된 개념의 검증을 위해 객체지향개념의 3-D 형상정보 계층과 구조계산서 정보계층으로 이루어진 시범 데이터베이스를 구축하였다. 또한 두 계층으로 분산되어 있는 데이터의 일치여부를 자동으로 검토하는 실험을 통하여 본 연구에서 제시된 멀티레이어 데이터베이스 개념이 교량정보를 관리하는데 있어 정보의 무결성과 일관성을 보장할 수 있음을 보였다.

• 대한기계학회논문집B
• /
• 제36권10호
• /
• pp.1025-1032
• /
• 2012

플래시 램프 열처리(Flash lamp annealing, FLA) 공정은 저온폴리실리콘의 생산을 위한 기술로써 대면적 기판용 실리콘 결정화 기술로 기대 받고 있는 기술이다. 본 연구에서는 FLA 공정 중 기판에 발생하는 변형의 원인에 대하여 이론적인 해석과 이를 토대로 시뮬레이션을 수행하였다. 상용 FEM 해석프로그램에 고온에서의 유리의 점성에 대한 모델을 적용하여, 고온에서 유리의 구조적인 수축과 응력이완으로 인한 영구변형을 수치적으로 재현하였다. 0 세대 실험시편($2cm{\times}2cm$)의 경우 중력의 영향이 미미하여서, 실험 결과와 일치하는 'U'모양의 변형이 남는 것을 확인하였고, 4 세대 기판($74cm{\times}94cm$)의 경우 중력으로 인하여 'M'모양의 변형이 발생하는 것을 시뮬레이션하였다.