Presentation 2019-06-18
Additive or Concatenating Skip-connections Overcome the Degradation Problem of the Classic Feedforward Neural Network
Yasutaka Furusho, Kazushi Ikeda,
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Abstract(in Japanese) (See Japanese page)
Abstract(in English) The classic feedforward neural networks like the multilayer perceptron (MLP) degrades its empirical risk by training even though it stacks more layers. To overcome this problem, the ResNet which has additive skip-connections and the DenseNet which has concatenating skip-connections were proposed. These skip-connections enable an extreme deep neural network (DNN) to be trained with high performance. However, the reasons for these successes and when to prefer the one skip-connection to the other are unclear. A large ratio of the between-class distance to the within-class distance of feature vectors at the last hidden layer induces a high performance. Thus, we analyzed the change of these distances through hidden layers of the randomly initialized MLP, the ResNet, and the DenseNet. Our results show that the MLP strongly decreases the between-class distance compared with the within-class distance and that both skip-connections relax this decrease of the between-class angle and improve the ratio of the distances. In particular, the concatenating skip-connection is more preferable to the additive skip-connection if a DNN is extremely deep. Moreover, the additive skip-connection relax the exponential decrease of the angle into the sub-exponential decrease and the concatenating skip-connection relax this decrease into the reciprocal decrease. We also analyzed the effects of training on the distances and show that the preservation of the angle through layers at initialization encourages trained neural networks to increase the ratio of the distances. Therefore, both skip-connections induce high performance.
Keyword(in Japanese) (See Japanese page)
Keyword(in English) Deep neural network / ResNet / DenseNet / Skip-connection
Paper # NC2019-17,IBISML2019-15
Date of Issue 2019-06-10 (NC, IBISML)

Conference Information
Committee NC / IBISML / IPSJ-MPS / IPSJ-BIO
Conference Date 2019/6/17(3days)
Place (in Japanese) (See Japanese page)
Place (in English) Okinawa Institute of Science and Technology
Topics (in Japanese) (See Japanese page)
Topics (in English) Neurocomputing, Machine Learning Approach to Biodata Mining, and General
Chair Hayaru Shouno(UEC) / Hisashi Kashima(Kyoto Univ.) / Masakazu Sekijima(Tokyo Tech) / Hiroyuki Kurata(Kyutech)
Vice Chair Kazuyuki Samejima(Tamagawa Univ) / Masashi Sugiyama(Univ. of Tokyo) / Koji Tsuda(Univ. of Tokyo)
Secretary Kazuyuki Samejima(NAIST) / Masashi Sugiyama(NTT) / Koji Tsuda(Nagoya Inst. of Tech.) / (AIST) / (Nagoya Univ.)
Assistant Takashi Shinozaki(NICT) / Ken Takiyama(TUAT) / Tomoharu Iwata(NTT) / Shigeyuki Oba(Kyoto Univ.)

Paper Information
Registration To Technical Committee on Neurocomputing / Technical Committee on Infomation-Based Induction Sciences and Machine Learning / IPSJ Special Interest Group on Mathematical Modeling and Problem Solving / IPSJ Special Interest Group on Bioinformatics and Genomics
Language JPN
Title (in Japanese) (See Japanese page)
Sub Title (in Japanese) (See Japanese page)
Title (in English) Additive or Concatenating Skip-connections Overcome the Degradation Problem of the Classic Feedforward Neural Network
Sub Title (in English)
Keyword(1) Deep neural network
Keyword(2) ResNet
Keyword(3) DenseNet
Keyword(4) Skip-connection
1st Author's Name Yasutaka Furusho
1st Author's Affiliation Nara Institute of Science and Technology(NAIST)
2nd Author's Name Kazushi Ikeda
2nd Author's Affiliation Nara Institute of Science and Technology(NAIST)
Date 2019-06-18
Paper # NC2019-17,IBISML2019-15
Volume (vol) vol.119
Number (no) NC-88,IBISML-89
Page pp.pp.75-80(NC), pp.97-102(IBISML),
#Pages 6
Date of Issue 2019-06-10 (NC, IBISML)