• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.5
• /
• pp.589-599
• /
• 2013

The concept of robust optimization is based on Taguchi's method. Especially, robustness indices of objective function pursue an insensitive and conservative design when there are variations on design variables and parameters. To accomplish the purpose, various robustness indices on the objective function have been developed. However, it can be caused limitations to develop the robustness index, because there is difference between the Taguchi's method and robust optimization. In this paper, an investigation is performed to identify the characteristics and the drawbacks of the previous studies. To achieve the purpose, evaluations are conducted by using the examples which have both a deterministic optimum and a robust optimum. Moreover, a new viewpoint as well as a robustness index using a supremum value of the objective function is proposed based on the investigation.

• Journal of KIISE
• /
• v.41 no.10
• /
• pp.774-784
• /
• 2014

Studies of fault-injection into state machine diagram have been studied for generating robustness test cases. Conventional studies have, however, tended to inject too many faults into diagrams because they only have considered structural aspects of diagrams. In this paper, we propose a method that aims to reduce the number of injected fault without a decrease in effectivenss of robustness test. A proposed method is demonstrated using a microwave oven sate machine diagram and evaluated using a hash table state machine diagram. The result of the evaluation shows that the number of injected faults is decreased by 43% and the number of test cases is decreased by 63% without a decrease in effectiveness of hash table robustness test.

• Proceedings of the Korea Contents Association Conference
• /
• 2003.11a
• /
• pp.213-217
• /
• 2003

In this paper, we analysize the noise robustness of MLPs(Multilayer perceptrons). Also, as a preprocessing stage of MLPs to improve noise robustness, we consider the ICA(independent component analysis) and PCA(principle component analysis). After analyzing the noise redunction effect using PCA or ICA, we verify the noise robustness of MLPs through handwritten-digit recognition simulations.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2022.11a
• /
• pp.510-512
• /
• 2022

컴퓨터 비전 분야에서 오랫동안 사용되었던 CNN(Convolution Neural Network)은 오분류를 일으키기 위해 악의적으로 추가된 섭동에 매우 취약하다. ViT(Vision Transformer)는 입력 이미지의 전체적인 특징을 탐색하는 어텐션 구조를 적용함으로 CNN의 국소적 특징 탐색보다 특성 픽셀에 섭동을 추가하는 적대적 공격에 강건한 특성을 보이지만 최근 어텐션 구조에 대한 강건성 분석과 다양한 공격 기법의 발달로 보안 취약성 문제가 제기되고 있다. 본 논문은 ViT가 CNN 대비 강건성을 가지는 구조적인 특징을 분석하는 연구와 어텐션 구조에 대한 최신 공격기법을 소개함으로 향후 등장할 ViT 파생 모델의 강건성을 유지하기 위해 중점적으로 다루어야 할 부분이 무엇인지 소개한다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.228-228
• /
• 2023

국지적 지역에 내리는 강한 강도의 강우는 많은 인명 및 재산 피해를 발생시킨다. 이러한 피해를 예방하기 위해 도시 침수 예측에 관한 연구가 오랜 기간 수행되어 왔으며, 최근에는 다양한 신경망(neural network) 모델이 활발히 이용되고 있다. 강우 지속 기간이나 강도는 일정하지 않고, 공간적 특징 또한 도시마다 다르므로 안정적인 침수 예측을 위한 신경망 모델은 강건성(robustness)을 지녀야 한다. 강건한 신경망 모델이란 적대적 공격(adversarial attack)을 방어할 수 있는 능력을 갖춘 모델을 일컫는다. 따라서 본 연구에서는, 도시 침수 예측을 위한 시공간 신경망(spatio-temporal neural network) 모델의 강건성 제고를 위한 방법론을 제안한다. 먼저 적대적 공격의 유형과 방어 방법을 분류하고, 시공간 신경망 모델의 학습 데이터 특성 및 모델 구조구성 조건 등을 활용하여 최적의 강건성 제고 방안을 도출하였다. 해당 모델은 집중호우로 인해 나타날 다양한 관망에서의 침수 피해를 각각 예측하고 피해를 예방하기 위해 활용될 수 있다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.04b
• /
• pp.355-357
• /
• 2004

Java의 경우 기존의 강건성 테스팅 방법인 ballista로는 객체 타입의 인자 및 파일 시스템의 변화를 시뮬레이션 할 수 없다. 따라서 객체에 대한 특별한 접근을 필요로 한다. 본 논문에서는 객체에 폴트를 삽입하는 방식을 통하여 자바 가상 기계의 강건성(Robustness)을 테스팅하는 방법을 제안한다. 자바 디버깅 툴인 JPDA를 사용하여 자바 가상 머신에 대한 직접적인 접근 및 의도한 상태 및 환경 변경을 가능하게 하고 이를 통해 자바 가상 기계에 폴트가 심어진 객체를 수행시킬 수 있다. 객체를 수행시키고 의도한 예외상황의 발생 유무를 관찰함으로써 자바 가상 기계의 강건성을 테스트 할 수 있다.

• Korean Journal of Poultry Science
• /
• v.48 no.1
• /
• pp.1-12
• /
• 2021

We investigated the effects of breed, laying age, and egg storage period on the vitality of chicks using the Hwanggalsaek Jaeraejong, Korean Rhode Island Red, and Korean White Leghorn chicken breeds. Their eggs were collected during the early laying period (27~29 weeks) and late laying period (50~52 weeks) and were stored for 3 days, 7 days and 14 days. After the eggs hatched, the hatching time, production performance, and organ weight of chicks were investigated. IL-6 gene expression level and relative length of telomeres were analyzed to determine the physiological activity of the chicks. HSP gene expression level and heterophil to lymphocytes ratio were also analyzed to examine the degree of stress response in the chicks. The results showed that breed and laying age influenced the vitality of chicks, but the egg storage period did not. Korean Leghorn chicks were considered the weakest breed in terms of vitality owing to their low survival rate, small heart size, low physiological activity, and high stress response level. Although the survival rate of chicks produced in the early laying period was low, their high physiological activity and low stress response indicated that they had a high vitality than the chicks produced in the late laying period. In conclusion, to obtain chicks with high vitality, it would be desirable to select a high vitality breed and avoid the use of chicks produced in the late laying period.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.5
• /
• pp.535-543
• /
• 2014

In the robust optimization field, the robustness of the objective function emphasizes an insensitive design. In general, the robustness of the objective function can be achieved by reducing the change of the objective function with respect to the variation of the design variables and parameters. However, in conventional methods, when an insensitive design is emphasized, the performance of the objective function can be deteriorated. Besides, if the numbers of the design variables are increased, the numerical cost is quite high in robust optimization for nonlinear programming problems. In this research, the robustness index for the objective function and a process of robust optimization are proposed. Moreover, a method using the supremum of linearized functions is also proposed to reduce the computational cost. Mathematical examples are solved for the verification of the proposed method and the results are compared with those from the conventional methods. The proposed approach improves the performance of the objective function and its efficiency.

• Journal of the Korea Society of Computer and Information
• /
• v.24 no.10
• /
• pp.205-213
• /
• 2019

Network robustness is one of the most important characteristics needed as the network. Over the military tactical communication network, robustness is a key function for maintaining attack phase constantly. Tactical Information Communication Network, called TICN, has mixed characteristics of lattice- and tree-type network topology, which looks somewhat weak in the viewpoint of network robustness. In this paper, we search articulation points and bridges in a current Tactical Information Communication Network using graph theory. To improve the weak points empirically searched, we try to add links to create the concrete network and then observe the change of network-based verification values through diminishing nodes. With these themes, we evaluate the generated networks through SNA techniques. Experimental results show that the generated networks' robustness is improved compared with current network structure.

• Journal of Korea Multimedia Society
• /
• v.9 no.5
• /
• pp.576-584
• /
• 2006

Content-based video matching is measuring a similarity of video signature compared to the original clip and copies of media. Specially, it is very important to match the exact frame position, but it depends on frame rate, noise condition and compression format of video. Ordinal signature shows good performance than other video signatures under normal condition but the previous didn't try to find the uniqueness and robustness. Hua et al. performed a uniqueness test under compressed in different formats or frame size. However, they used other compression format image instead of noise in robustness test. This paper proposes robustness test method using several noise models and analyzes the performance of robustness and uniqueness.