A Lightweight 1-D Convolution Augmented Transformer with Metric Learning for Hyperspectral Image Classification

Hyperspectral image (HSI) classification is the subject of intense research in remote sensing. The tremendous success of deep learning in computer vision has recently sparked the interest in applying deep learning in hyperspectral image classification. However, most deep learning methods for hypersp...

Full description

Saved in:
Bibliographic Details
Published inSensors (Basel, Switzerland) Vol. 21; no. 5; p. 1751
Main Authors Hu, Xiang, Yang, Wenjing, Wen, Hao, Liu, Yu, Peng, Yuanxi
Format Journal Article
LanguageEnglish
Published Switzerland MDPI 03.03.2021
MDPI AG
Subjects
Online AccessGet full text

Cover

Loading…
Abstract Hyperspectral image (HSI) classification is the subject of intense research in remote sensing. The tremendous success of deep learning in computer vision has recently sparked the interest in applying deep learning in hyperspectral image classification. However, most deep learning methods for hyperspectral image classification are based on convolutional neural networks (CNN). Those methods require heavy GPU memory resources and run time. Recently, another deep learning model, the transformer, has been applied for image recognition, and the study result demonstrates the great potential of the transformer network for computer vision tasks. In this paper, we propose a model for hyperspectral image classification based on the transformer, which is widely used in natural language processing. Besides, we believe we are the first to combine the metric learning and the transformer model in hyperspectral image classification. Moreover, to improve the model classification performance when the available training samples are limited, we use the 1-D convolution and Mish activation function. The experimental results on three widely used hyperspectral image data sets demonstrate the proposed model’s advantages in accuracy, GPU memory cost, and running time.
AbstractList Hyperspectral image (HSI) classification is the subject of intense research in remote sensing. The tremendous success of deep learning in computer vision has recently sparked the interest in applying deep learning in hyperspectral image classification. However, most deep learning methods for hyperspectral image classification are based on convolutional neural networks (CNN). Those methods require heavy GPU memory resources and run time. Recently, another deep learning model, the transformer, has been applied for image recognition, and the study result demonstrates the great potential of the transformer network for computer vision tasks. In this paper, we propose a model for hyperspectral image classification based on the transformer, which is widely used in natural language processing. Besides, we believe we are the first to combine the metric learning and the transformer model in hyperspectral image classification. Moreover, to improve the model classification performance when the available training samples are limited, we use the 1-D convolution and Mish activation function. The experimental results on three widely used hyperspectral image data sets demonstrate the proposed model's advantages in accuracy, GPU memory cost, and running time.
Hyperspectral image (HSI) classification is the subject of intense research in remote sensing. The tremendous success of deep learning in computer vision has recently sparked the interest in applying deep learning in hyperspectral image classification. However, most deep learning methods for hyperspectral image classification are based on convolutional neural networks (CNN). Those methods require heavy GPU memory resources and run time. Recently, another deep learning model, the transformer, has been applied for image recognition, and the study result demonstrates the great potential of the transformer network for computer vision tasks. In this paper, we propose a model for hyperspectral image classification based on the transformer, which is widely used in natural language processing. Besides, we believe we are the first to combine the metric learning and the transformer model in hyperspectral image classification. Moreover, to improve the model classification performance when the available training samples are limited, we use the 1-D convolution and Mish activation function. The experimental results on three widely used hyperspectral image data sets demonstrate the proposed model's advantages in accuracy, GPU memory cost, and running time.Hyperspectral image (HSI) classification is the subject of intense research in remote sensing. The tremendous success of deep learning in computer vision has recently sparked the interest in applying deep learning in hyperspectral image classification. However, most deep learning methods for hyperspectral image classification are based on convolutional neural networks (CNN). Those methods require heavy GPU memory resources and run time. Recently, another deep learning model, the transformer, has been applied for image recognition, and the study result demonstrates the great potential of the transformer network for computer vision tasks. In this paper, we propose a model for hyperspectral image classification based on the transformer, which is widely used in natural language processing. Besides, we believe we are the first to combine the metric learning and the transformer model in hyperspectral image classification. Moreover, to improve the model classification performance when the available training samples are limited, we use the 1-D convolution and Mish activation function. The experimental results on three widely used hyperspectral image data sets demonstrate the proposed model's advantages in accuracy, GPU memory cost, and running time.
Author Peng, Yuanxi
Liu, Yu
Yang, Wenjing
Wen, Hao
Hu, Xiang
AuthorAffiliation The State Key Laboratory of High-Performance Computing, College of Computer, National University of Defense Technology, Changsha 410000, China; huxiang@nudt.edu.cn (X.H.); wenjing.yang@nudt.edu.cn (W.Y.); hao.wen@nudt.edu.cn (H.W.); liuyu11@nudt.edu.cn (Y.L.)
AuthorAffiliation_xml – name: The State Key Laboratory of High-Performance Computing, College of Computer, National University of Defense Technology, Changsha 410000, China; huxiang@nudt.edu.cn (X.H.); wenjing.yang@nudt.edu.cn (W.Y.); hao.wen@nudt.edu.cn (H.W.); liuyu11@nudt.edu.cn (Y.L.)
Author_xml – sequence: 1
  givenname: Xiang
  orcidid: 0000-0002-1798-8508
  surname: Hu
  fullname: Hu, Xiang
– sequence: 2
  givenname: Wenjing
  surname: Yang
  fullname: Yang, Wenjing
– sequence: 3
  givenname: Hao
  surname: Wen
  fullname: Wen, Hao
– sequence: 4
  givenname: Yu
  surname: Liu
  fullname: Liu, Yu
– sequence: 5
  givenname: Yuanxi
  surname: Peng
  fullname: Peng, Yuanxi
BackLink https://www.ncbi.nlm.nih.gov/pubmed/33802533$$D View this record in MEDLINE/PubMed
BookMark eNptks1vFCEUwCemxn7owX_AcNTDWj4H5mKy2ardZI2XeiYM82aWZgZWYNr0v5ft1k1rvADh_fg94L3z6sQHD1X1nuDPjDX4MlGCBZGCvKrOCKd8oSjFJ8_Wp9V5SrcYU8aYelOdlhFTwdhZFZZo44Ztvof9iMjiCq2CvwvjnF3waDkPE_gMHbqJxqc-xAkiund5i35Ajs6iDZjonR9QiaHrhx3EtAOboxnRejIDoNVoUnK9s2ZvfFu97s2Y4N3TfFH9-vb1ZnW92Pz8vl4tNwvLOckLUTe9MhgEs12NrREUJNRCEmJI31gmhOW24bRrOqYkkU3Ty56BqXvFWAeMXVTrg7cL5lbvoptMfNDBOP24EeKgTczOjqCFNEJwYKa1tEht23CGVaswbrkiau_6cnDt5naCzpYPKc97IX0Z8W6rh3CnZVMTKUURfHwSxPB7hpT15JKFcTQewpw0FViJmmFOC_rhea5jkr8VK8CnA2BjSClCf0QI1vtu0MduKOzlP6x1-bEM5Zpu_M-JP_MbtrI
CitedBy_id crossref_primary_10_1109_JSTARS_2022_3174135
crossref_primary_10_3390_diagnostics13193054
crossref_primary_10_1109_TGRS_2023_3244805
crossref_primary_10_1155_2022_7071485
crossref_primary_10_1155_2023_4305594
crossref_primary_10_1109_TGRS_2023_3277014
crossref_primary_10_3390_rs15102696
crossref_primary_10_1007_s10462_024_10877_1
crossref_primary_10_1080_01431161_2023_2297178
crossref_primary_10_3390_rs13163176
crossref_primary_10_1109_MGRS_2024_3489613
crossref_primary_10_1111_1750_3841_17512
crossref_primary_10_1109_TGRS_2023_3321840
crossref_primary_10_3390_drones7040240
crossref_primary_10_1109_TGRS_2024_3384403
crossref_primary_10_3788_LOP232211
crossref_primary_10_1155_2022_2974960
crossref_primary_10_1155_2023_9150482
crossref_primary_10_3390_rs15184592
crossref_primary_10_1016_j_neucom_2023_02_006
crossref_primary_10_1080_01431161_2022_2102952
Cites_doi 10.1109/JSTARS.2014.2329330
10.1109/TGRS.2017.2783902
10.1109/TGRS.2016.2584107
10.1109/TGRS.2018.2869004
10.1109/TGRS.2018.2818945
10.1109/ICIP.2017.8297014
10.1080/2150704X.2017.1331053
10.1109/TPAMI.2016.2577031
10.1109/LGRS.2017.2737823
10.1016/j.ecoinf.2014.07.004
10.1109/ICPR.2018.8546126
10.1109/IJCNN.2019.8852422
10.1109/LGRS.2019.2918719
10.1109/ICCV.2017.322
10.1109/CVPR.2019.00074
10.1109/ICASSP.2019.8682194
10.1007/s00371-021-02058-w
10.3390/rs8020099
10.1109/JSTARS.2016.2517204
10.1007/978-3-319-46478-7_31
10.1109/TGRS.2017.2686842
10.1109/IGARSS.2017.8126919
10.1109/JSTARS.2015.2388577
ContentType Journal Article
Copyright 2021 by the authors. 2021
Copyright_xml – notice: 2021 by the authors. 2021
DBID AAYXX
CITATION
NPM
7X8
5PM
DOA
DOI 10.3390/s21051751
DatabaseName CrossRef
PubMed
MEDLINE - Academic
PubMed Central (Full Participant titles)
DOAJ Directory of Open Access Journals
DatabaseTitle CrossRef
PubMed
MEDLINE - Academic
DatabaseTitleList PubMed

MEDLINE - Academic

CrossRef
Database_xml – sequence: 1
  dbid: DOA
  name: DOAJ Directory of Open Access Journals
  url: https://www.doaj.org/
  sourceTypes: Open Website
– sequence: 2
  dbid: NPM
  name: PubMed
  url: https://proxy.k.utb.cz/login?url=http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed
  sourceTypes: Index Database
DeliveryMethod fulltext_linktorsrc
Discipline Engineering
EISSN 1424-8220
ExternalDocumentID oai_doaj_org_article_57a554e3abc24c9cb94308b800b48183
PMC7961775
33802533
10_3390_s21051751
Genre Journal Article
GrantInformation_xml – fundername: National Natural Science Foundation of China
  grantid: No.91648204 and 61803375
– fundername: National Key Research and Development Program of China
  grantid: No.2017YFB1301104 and 2017YFB1001900
GroupedDBID ---
123
2WC
53G
5VS
7X7
88E
8FE
8FG
8FI
8FJ
AADQD
AAHBH
AAYXX
ABDBF
ABUWG
ACUHS
ADBBV
ADMLS
AENEX
AFKRA
AFZYC
ALIPV
ALMA_UNASSIGNED_HOLDINGS
BENPR
BPHCQ
BVXVI
CCPQU
CITATION
CS3
D1I
DU5
E3Z
EBD
ESX
F5P
FYUFA
GROUPED_DOAJ
GX1
HH5
HMCUK
HYE
IAO
ITC
KQ8
L6V
M1P
M48
MODMG
M~E
OK1
OVT
P2P
P62
PHGZM
PHGZT
PIMPY
PQQKQ
PROAC
PSQYO
RNS
RPM
TUS
UKHRP
XSB
~8M
3V.
ABJCF
ARAPS
HCIFZ
KB.
M7S
NPM
PDBOC
7X8
PPXIY
5PM
PJZUB
PUEGO
ID FETCH-LOGICAL-c441t-569f8a0e53cd60ca52e7e65711a1f9c355c4c942d9d3871799f7f3ea6f833de33
IEDL.DBID M48
ISSN 1424-8220
IngestDate Wed Aug 27 01:26:24 EDT 2025
Thu Aug 21 18:13:45 EDT 2025
Fri Jul 11 10:33:40 EDT 2025
Wed Feb 19 02:27:56 EST 2025
Tue Jul 01 03:56:06 EDT 2025
Thu Apr 24 23:07:23 EDT 2025
IsDoiOpenAccess true
IsOpenAccess true
IsPeerReviewed true
IsScholarly true
Issue 5
Keywords transformer
deep learning
remote sensing
metric learning
hyperspectral image classification
1-D convolution
Language English
License https://creativecommons.org/licenses/by/4.0
Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
LinkModel DirectLink
MergedId FETCHMERGED-LOGICAL-c441t-569f8a0e53cd60ca52e7e65711a1f9c355c4c942d9d3871799f7f3ea6f833de33
Notes ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ORCID 0000-0002-1798-8508
OpenAccessLink http://journals.scholarsportal.info/openUrl.xqy?doi=10.3390/s21051751
PMID 33802533
PQID 2508563042
PQPubID 23479
ParticipantIDs doaj_primary_oai_doaj_org_article_57a554e3abc24c9cb94308b800b48183
pubmedcentral_primary_oai_pubmedcentral_nih_gov_7961775
proquest_miscellaneous_2508563042
pubmed_primary_33802533
crossref_primary_10_3390_s21051751
crossref_citationtrail_10_3390_s21051751
ProviderPackageCode CITATION
AAYXX
PublicationCentury 2000
PublicationDate 20210303
PublicationDateYYYYMMDD 2021-03-03
PublicationDate_xml – month: 3
  year: 2021
  text: 20210303
  day: 3
PublicationDecade 2020
PublicationPlace Switzerland
PublicationPlace_xml – name: Switzerland
PublicationTitle Sensors (Basel, Switzerland)
PublicationTitleAlternate Sensors (Basel)
PublicationYear 2021
Publisher MDPI
MDPI AG
Publisher_xml – name: MDPI
– name: MDPI AG
References Zhang (ref_14) 2017; 14
Chen (ref_16) 2016; 54
Ma (ref_13) 2016; 9
Chen (ref_12) 2014; 7
ref_11
ref_10
Roy (ref_17) 2019; 17
Sun (ref_3) 2017; 55
Awad (ref_4) 2014; 24
Guo (ref_19) 2018; 57
Cheng (ref_18) 2018; 56
Hamida (ref_26) 2018; 56
Vaswani (ref_20) 2017; 30
ref_24
ref_23
ref_22
ref_21
ref_1
ref_2
ref_27
Liu (ref_25) 2017; 8
ref_8
Chen (ref_15) 2015; 8
ref_5
ref_7
ref_6
Ren (ref_9) 2016; 39
References_xml – volume: 7
  start-page: 2094
  year: 2014
  ident: ref_12
  article-title: Deep learning-based classification of hyperspectral data
  publication-title: IEEE J. Sel. Top. Appl. Earth Obs. Remote. Sens.
  doi: 10.1109/JSTARS.2014.2329330
– volume: 56
  start-page: 2811
  year: 2018
  ident: ref_18
  article-title: When deep learning meets metric learning: Remote sensing image scene classification via learning discriminative cnns
  publication-title: IEEE Trans. Geosci. Remote. Sens.
  doi: 10.1109/TGRS.2017.2783902
– volume: 54
  start-page: 6232
  year: 2016
  ident: ref_16
  article-title: Deep feature extraction and classification of hyperspectral images based on convolutional neural networks
  publication-title: IEEE Trans. Geosci. Remote. Sens.
  doi: 10.1109/TGRS.2016.2584107
– volume: 57
  start-page: 1755
  year: 2018
  ident: ref_19
  article-title: Spectral-spatial feature extraction and classification by ann supervised with center loss in hyperspectral imagery
  publication-title: IEEE Trans. Geosci. Remote. Sens.
  doi: 10.1109/TGRS.2018.2869004
– ident: ref_5
– volume: 56
  start-page: 4420
  year: 2018
  ident: ref_26
  article-title: 3-d deep learning approach for remote sensing image classification
  publication-title: IEEE Trans. Geosci. Remote. Sens.
  doi: 10.1109/TGRS.2018.2818945
– ident: ref_27
  doi: 10.1109/ICIP.2017.8297014
– volume: 8
  start-page: 839
  year: 2017
  ident: ref_25
  article-title: A semi-supervised convolutional neural network for hyperspectral image classification
  publication-title: Remote. Sens. Lett.
  doi: 10.1080/2150704X.2017.1331053
– volume: 39
  start-page: 1137
  year: 2016
  ident: ref_9
  article-title: Faster r-cnn: Towards real-time object detection with region proposal networks
  publication-title: IEEE Trans. Pattern Anal. Mach. Intell.
  doi: 10.1109/TPAMI.2016.2577031
– volume: 14
  start-page: 1928
  year: 2017
  ident: ref_14
  article-title: Recursive autoencoders-based unsupervised feature learning for hyperspectral image classification
  publication-title: IEEE Geosci. Remote. Sens. Lett.
  doi: 10.1109/LGRS.2017.2737823
– volume: 24
  start-page: 60
  year: 2014
  ident: ref_4
  article-title: Sea water chlorophyll-a estimation using hyperspectral images and supervised artificial neural network
  publication-title: Ecol. Inform.
  doi: 10.1016/j.ecoinf.2014.07.004
– ident: ref_21
– ident: ref_8
  doi: 10.1109/ICPR.2018.8546126
– ident: ref_11
  doi: 10.1109/IJCNN.2019.8852422
– volume: 17
  start-page: 277
  year: 2019
  ident: ref_17
  article-title: Hybridsn: Exploring 3-d–2-d cnn feature hierarchy for hyperspectral image classification
  publication-title: IEEE Geosci. Remote. Sens. Lett.
  doi: 10.1109/LGRS.2019.2918719
– ident: ref_10
  doi: 10.1109/ICCV.2017.322
– ident: ref_6
  doi: 10.1109/CVPR.2019.00074
– ident: ref_23
  doi: 10.1109/ICASSP.2019.8682194
– ident: ref_7
  doi: 10.1007/s00371-021-02058-w
– ident: ref_2
  doi: 10.3390/rs8020099
– volume: 9
  start-page: 4073
  year: 2016
  ident: ref_13
  article-title: Spectral–spatial classification of hyperspectral image based on deep auto-encoder
  publication-title: IEEE J. Sel. Top. Appl. Earth Obs. Remote. Sens.
  doi: 10.1109/JSTARS.2016.2517204
– ident: ref_24
  doi: 10.1007/978-3-319-46478-7_31
– volume: 55
  start-page: 4032
  year: 2017
  ident: ref_3
  article-title: A sparse and low-rank near-isometric linear embedding method for feature extraction in hyperspectral imagery classification
  publication-title: IEEE Trans. Geosci. Remote. Sens.
  doi: 10.1109/TGRS.2017.2686842
– ident: ref_1
  doi: 10.1109/IGARSS.2017.8126919
– volume: 30
  start-page: 5998
  year: 2017
  ident: ref_20
  article-title: Attention is all you need
  publication-title: Adv. Neural Inf. Process. Syst.
– volume: 8
  start-page: 2381
  year: 2015
  ident: ref_15
  article-title: Spectral–spatial classification of hyperspectral data based on deep belief network
  publication-title: IEEE J. Sel. Top. Appl. Earth Obs. Remote. Sens.
  doi: 10.1109/JSTARS.2015.2388577
– ident: ref_22
SSID ssj0023338
Score 2.4559104
Snippet Hyperspectral image (HSI) classification is the subject of intense research in remote sensing. The tremendous success of deep learning in computer vision has...
SourceID doaj
pubmedcentral
proquest
pubmed
crossref
SourceType Open Website
Open Access Repository
Aggregation Database
Index Database
Enrichment Source
StartPage 1751
SubjectTerms 1-D convolution
deep learning
hyperspectral image classification
metric learning
remote sensing
transformer
SummonAdditionalLinks – databaseName: DOAJ Directory of Open Access Journals
  dbid: DOA
  link: http://utb.summon.serialssolutions.com/2.0.0/link/0/eLvHCXMwrV07T8MwELYQEwyIN-UlgxhYIhKfE9tjeakgYKJStyjxoyBBikoLf5-zk1YtqsTCGjvKyXfJfZ9z_o6QM8cAMmBpFDu_dSO5jqTkJiqMUwKy2CbCn3d-fMo6XX7fS3szrb58TVgtD1wvHBL2AjOehaLUjGulS68XLkvEOSXHZBN0PjHnTchUQ7UAmVetIwRI6i8-kdikmCiTuewTRPoXIcvfBZIzGed2naw1UJG2axM3yJKtNsnqjIDgFhm06YNn199hg5Mm0TW9GlRfTTjR9rgfNDcNfZ7gUzukfuuVPvpOWpo28qp9imO0g5y0PnqJ1tC7d_zU0NA005cTBQ9uk-7tzfNVJ2paKEQacc4oSjPlZBHbFLTJYl2kzAqbpSJJisQpjWBD46JyZpQBpE5CKScc2CJzEsBYgB2yXA0qu0doDM4YlRjBneE6htJpyzOjRcliZqVskfPJ0ua60Rf3bS7ecuQZ3gv51Astcjqd-lGLaiyadOn9M53gdbDDBYyOvImO_K_oaJGTiXdzfG_8z5CisoPxZ47QT3ptNM5aZLf29vRRGDwIBQHvFnNxMGfL_Ej1-hK0uYVCSCjS_f8w_oCsMF9B4yve4JAsj4Zje4QQaFQeh2j_AfklBX8
  priority: 102
  providerName: Directory of Open Access Journals
Title A Lightweight 1-D Convolution Augmented Transformer with Metric Learning for Hyperspectral Image Classification
URI https://www.ncbi.nlm.nih.gov/pubmed/33802533
https://www.proquest.com/docview/2508563042
https://pubmed.ncbi.nlm.nih.gov/PMC7961775
https://doaj.org/article/57a554e3abc24c9cb94308b800b48183
Volume 21
hasFullText 1
inHoldings 1
isFullTextHit
isPrint
link http://utb.summon.serialssolutions.com/2.0.0/link/0/eLvHCXMwjV1Jb9QwFLZKe4EDYu9QGBnEgUsg8RI7B4SmpcOAmAqhjjS3KPEyIJWEzgL03_c9JxM1aA5ccoht2fGz877Py_cIeeUZ5ylnMoo9Lt1oYSKthY0K6zPF09glCu87T8_SyUx8nsv5HtnG2Gw7cLWT2mE8qdny4s3fy6v3MOHfIeMEyv52BbRFghsEEnQADklhIIOp6DYToDUhoDXe6YrAH8aNwFC_aM8tBfX-XZDz35OTN1zR-B6522JIOmqMfp_sueoBuXNDWfAhqUf0C9LuP2HlkybRB3pSV7_bcUZHm0UQ47T0fAtc3ZLimiydYogtQ1vd1QWFNDoBstrcyYTW0E8_4R9EQzRNPGcUTPuIzMan5yeTqI2tEBkAQOtIppnXRewkNzaNTSGZUy6VKkmKxGcGUIgRJhPMZpYDp1JZ5pXnrki95tw6zh-T_aqu3CGhMffWZolVwlthYl5640RqjSpZzJzWA_J627W5aYXHMf7FRQ4EBK2Qd1YYkJdd1l-N2sauTMdony4DCmSHF_VykbfzLZeqAKDkeFEaBh9iSpSZ1yXA41IARuED8mJr3RwmFO6SFJWrN6scMKFG0TTBBuRJY-2uKhhIgBE5lFa9cdBrSz-l-vE9iHarDLCikk__o94jcpvhyRk86cafkf31cuOeA_RZl0NyS80VPPX445AcHJ-eff02DMsIwzDkrwHsMQdJ
linkProvider Scholars Portal
openUrl ctx_ver=Z39.88-2004&ctx_enc=info%3Aofi%2Fenc%3AUTF-8&rfr_id=info%3Asid%2Fsummon.serialssolutions.com&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=A+Lightweight+1-D+Convolution+Augmented+Transformer+with+Metric+Learning+for+Hyperspectral+Image+Classification&rft.jtitle=Sensors+%28Basel%2C+Switzerland%29&rft.au=Hu%2C+Xiang&rft.au=Yang%2C+Wenjing&rft.au=Wen%2C+Hao&rft.au=Liu%2C+Yu&rft.date=2021-03-03&rft.issn=1424-8220&rft.eissn=1424-8220&rft.volume=21&rft.issue=5&rft_id=info:doi/10.3390%2Fs21051751&rft.externalDBID=NO_FULL_TEXT
thumbnail_l http://covers-cdn.summon.serialssolutions.com/index.aspx?isbn=/lc.gif&issn=1424-8220&client=summon
thumbnail_m http://covers-cdn.summon.serialssolutions.com/index.aspx?isbn=/mc.gif&issn=1424-8220&client=summon
thumbnail_s http://covers-cdn.summon.serialssolutions.com/index.aspx?isbn=/sc.gif&issn=1424-8220&client=summon