• 한국지능시스템학회논문지
• /
• 제12권5호
• /
• pp.462-466
• /
• 2002

GA(Genetic Algorithm)는 자연계 진화를 모방한 계산 알고리즘으로서 단순하고 응용이 쉽기 때문에 여러 분야에 전역적 최적해 탐색에 많이 사용되고 있다. 최근에는 하드웨어를 구성하는 방법의 하나로서 사용되어 진화하드웨어라는 분야를 탄생시켰다. 이와 함께 GA의 연산자체를 하드웨어로 구현하는 GA processor(GAP)의 필요성도 증가하고 있다. 특히 진화하드웨어를 소프트웨어에서 진화시키는 것이 아닌 GAP에 의해 진화시키는 것은 독립된 구조의 진정한 EHW 설계에 필수적이 될 것이다. 본 논문에서는 진화하드웨어의 빠른 재구성을 위한 유전자 알고리즘 프로세서를 설계한다.

• Structural Engineering and Mechanics
• /
• 제62권2호
• /
• 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.

• 융합보안논문지
• /
• 제17권2호
• /
• pp.41-51
• /
• 2017

인터넷 활용 범위의 폭발적인 증가는 점차적으로 네트워크 속도와 용량을 초고속화 하고 대용량화로 빠르게 진화해 가고 있다. 이에 따라 스위치 라우터 등 네트워크 장비들은 하드웨어에 기반 한 빠른 기술 진화로 대처를 하고 있으나 초연결사회에 가장 기본적이고 필수적인 네트워크 보안시스템의 기술 진화는 수만 가지의 보안 이슈와 시그니처(signature)에 대해서 수시 변경과 갱신을 필요로 하기 때문에 소프트웨어에 기반 한 기술적인 한계를 극복하기가 쉽지 않다. 본 논문은 이와 같은 DDoS 대응 장비를 설치 운영할 때의 패킷 필터링 속도 저하 문제점을 개선하고자 FPGA(Field Programmable Gate Array)의 하드웨어적인 특성과 병렬처리 특성을 최대한 반영한 DPI 알고리즘인 Hi-DPI를 제안하고 실용성을 검증하고자 한다.

• 한국정보과학회:학술대회논문집
• /
• 한국정보과학회 2005년도 한국컴퓨터종합학술대회 논문집 Vol.32 No.1 (B)
• /
• pp.304-306
• /
• 2005

아키텍쳐(Architecture)는 프로젝트 초기에 결정된 설계 결정사항을 기재해 놓은 산출물이고 프로젝트 관련자(Stakeholder)간 의사소통의 수단이다. 아키텍쳐가 안정되어야 향후 진화(Evolution) 과정 중에 시스템을 이해하고 예측 관리하는 것이 쉬워지고 또한 기본 구조를 변경하지 않고 여러 가지 기능을 추가할 수 있다. 아키텍쳐 안정성(Architecture Stability)이란 진화과정 중에 발생하는 변경들을 견디는 정도를 말하고 변경은 적응변경(Adaptive Changes), 교정변경(Corrective Changes), 완전변경(Perfective Changes )을 포함한다. 그런데 진화 과정 동안에 변경들은 필연적으로 발생하게 되고 그로 인해 결정된 아키텍쳐는 본래의 모습을 그대로 유지할 수 없게 된다. 따라서 진화 과정시 아키텍쳐의 안정성을 측정하고 향후 변경에 대한 대비가 필요하다. 본 논문은 변경의 크기, 변경의 횟수, 변경의 종류와 아키텍쳐 불안정성의 관계를 버전별로 연구하고 그와 관련된 매트릭을 제안한다. 매트릭을 실제 프로젝트(Ant,JDT)에 적용하고 측정된 결과를 통해 아키텍쳐 안정성을 살펴봄으로써, 향후 안정성을 고려하여 아키텍쳐를 관리하고 개발하는데 도움을 줄 수 있을 것이다.

• Computers and Concrete
• /
• 제25권2호
• /
• pp.181-192
• /
• 2020

Nowadays, steel fiber reinforced concretes (SFRCs) are widely used in practical applications. Significant experimental research has thus been carried out to determine the constitutive equations that represent the behavior of SFRCs under multiaxial loadings. However, numerical modelling of SFRCs via FEM has been challenging due to the complexities of the implementation of these constitutive equations. In this study, following the literature, a plasticity model is constructed for the behavior of SFRCs that involves the Willam-Warnke failure surface with the relevant evolution laws and a non-associated flow rule for determining the plastic deformations. For the precise (yet rapid) integration of the constitutive equations, an explicit substepping scheme consisting of yield intersection and drift correction algorithms is employed and thus implemented in ABAQUS via UMAT. The FEM model includes various material parameters that are determined from the experimental data. Three sets of parameters are used in the numerical simulations. While the first set is from the experiments that are conducted in this study on SFRC specimens with various contents of steel fibers, the other two sets are from the experiments reported in the literature. The response of SFRCs under multiaxial compression obtained from various numerical simulations are compared with the experimental data. The good agreement between numerical results and the experimental data indicates that not only the adopted plasticity model represents the behavior of SFRCs very well but also the implemented integration scheme can be employed in practical applications of SFRCs.

• International Journal of Computer Science & Network Security
• /
• 제21권12spc호
• /
• pp.375-382
• /
• 2021

The paper introduces a model for evaluating and prioritizing mobile quality attributes and refactoring techniques through the examination of their effectiveness during the mobile application development process. The astonishing evolution of software and hardware has increased the demand for techniques and best practices to overcome the many challenges related to mobile devices, such as those concerning device storage, network bandwidth, and energy consumption. A number of studies have investigated the influence of refactoring, leading to the enhancement of mobile applications and the overcoming of code issues as well as hardware issues. Furthermore, rapid and continuous mobile developments make it necessary for teams to apply effective techniques to produce reliable mobile applications and reduce time to market. Thus, we investigated the influence of various refactoring techniques on mobile applications to understand their effectiveness in terms of quality attributes. First, we extracted the most important mobile refactoring techniques and a set of quality attributes from the literature. Then, mobile application developers from nine mobile application teams were recruited to evaluate and prioritize these quality attributes and refactoring techniques for their projects. A prioritization-based model is examined that integrates the lightweight multi-criteria decision making method, called the best-worst method, with the process of refactoring within mobile applications. The results prove the applicability and suitability of adopting the model for the mobile development process in order to expedite application production while using well-defined procedures to select the best refactoring techniques. Finally, a variety of quality attributes are shown to be influenced by the adoption of various refactoring techniques.

• 디지털산업정보학회논문지
• /
• 제14권4호
• /
• pp.79-85
• /
• 2018

This paper presents an implementation method of Long Term Evolution-Advanced (LTE-A) Physical Downlink Shared Channel (PDSCH) decoder using a general-purpose multicore Digital Signal Processor (DSP), TMS320C6670. Although the DSP provides some useful coprocessors such as turbo decoder, fast Fourier transformer, Viterbi Coprocessor, Bit Rate Coprocessor etc., it is specific to the base station platform implementation not the mobile terminal platform implementation. This paper shows an implementation method of the LTE-A PDSCH decoder using programmable DSP cores as well as the coprocessors of Fast Fourier Transformer and turbo decoder. First, it uses the coprocessor supported by the TMS320C6670, which can be used for PDSCH implementation. Second, we propose a core programming method using DSP optimization method for block diagram of PDSCH that can not use coprocessor. Through the implementation, we have verified a real-time decoding feasibility for the LTE-A downlink physical channel using test vectors which have been generated from LTE-A Reference Measurement Channel (RMC) Waveform R.6.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2016년도 추계학술대회
• /
• pp.846-847
• /
• 2016

LED 조명은 IT융합 시대로의 진화에 따라 단순조명에서 인간중심화/다기능화 시스템 조명으로 발전하였고 그로 인해 다양한 센서기능, 통신기능 등의 IT기술과 소프트웨어를 융합시켜 사용 환경변화에 따른 조명 제어로 에너지를 절감하고, 빛의 세기와 색조절로 사용자 중심의 맞춤형 조명이 요구 되고 있다. 이러한 지능화된 시스템 조명을 위해서는 사용자 중심의 센서 적용 및 제어가 가능해야하며 이를 위한 통신 모듈의 플랫폼화가 필요하다. 이에 본 논문에서는 LED 조명관제를 위해 블루투스 BLE를 활용한 통신모듈 플랫폼을 제안하였다.

• 대한건축학회논문집:구조계
• /
• 제34권2호
• /
• pp.11-17
• /
• 2018

Concrete is the well-used material in many architectural and civil structures. The behavior of concrete does exhibit a different characteristic in compression and tension, and it also shows an inelastic-nonlinear behavior. In addition, the concrete properties vary slightly depending on the environmental factor and manufacturer. These properties of concrete make the modeling or simulation of concrete material difficult. In reinforced concrete, particularly, there is a difficulty in bond-slip relationship between concrete and steel. However, in this paper, reserving remainder of these limits the finite element analysis for reinforced concrete beams through ABAQUS simulation has been carried out with some assumptions. Assumptions include the perfect bond of steel and concrete as well as the concrete damaged plasticity (CDP) in concrete property. There is a reasonable agreement between the experimental and numerical results, although the analytical strength and external rod deformation are slightly overestimated. The average and standard deviation between two results are 1.05 and 0.05, respectively. And the models and the computations lead to the evolution of fracture in bending beam.

• Computers and Concrete
• /
• 제27권2호
• /
• pp.153-162
• /
• 2021

This paper aims to simulate the isotropic elastic damage theory of Liu Jun (2012) using the self-programmed UMAT subroutine in the interface of ABAQUS. Liu Jun (2012)'s method based on the mechanic theory can not be used interactively with the currently commonly used finite element software ABAQUS. The advantage of this method in the paper is that it can interact with ABAQUS and provide a constitutive program framework that can be modified according to user need. The model retains the two scalar damage variables and the corresponding two energy dissipation mechanisms and damage criteria for considering the tensile and compressive asymmetry of concrete. Taking C45 concrete as an example, the relevant damage evolution parameters of its tensile and compressive constitutive model are given. The study demonstrates that the uniaxial tensile stress calculated by the subroutine is almost the same as the Chinese Concrete Design Specification (GB50010) before the peak stress, but ends soon after the peak stress. The stress-strain curve of uniaxial compression calculated by the subroutine is in good agreement with the peak stress in Chinese Concrete Design Specification (GB50010), but there is a certain deviation in the descending stage. In addition, this paper uses the newly compiled subroutine to simulate the shear bearing capacity of the shear key in a new structural system, namely the open-web sandwich slab. The results show that the damage constitutive subroutine has certain reliability.