Hiroshi FUJIWARA


Overloaded Wireless MIMO Switching for Information Exchanging through Untrusted Relay in Secure Wireless Communication
Arata TAKAHASHI Osamu TAKYU Hiroshi FUJIWARA Takeo FUJII Tomoaki OHTSUKI 
Publication:   
Publication Date: 2021/10/01
Vol. E104-B  No. 10  pp. 1249-1259
Type of Manuscript:  Special Section PAPER (Special Section on Dynamic Spectrum Sharing for Future Wireless Systems)
Category: 
Keyword: 
wireless MIMO switchingphysical layer securitymathematical optimization
 Summary | Full Text:PDF(2MB)

Analysis of Lower Bounds for Online Bin Packing with Two Item Sizes
Hiroshi FUJIWARA Ken ENDO Hiroaki YAMAMOTO 
Publication:   
Publication Date: 2021/09/01
Vol. E104-A  No. 9  pp. 1127-1133
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: Algorithms and Data Structures
Keyword: 
bin packing problemonline algorithmcompetitive analysismathematical optimization
 Summary | Full Text:PDF(1.1MB)

Asymptotic Approximation Ratios for Certain Classes of Online Bin Packing Algorithms
Hiroshi FUJIWARA Yuta WANIKAWA Hiroaki YAMAMOTO 
Publication:   
Publication Date: 2021/03/01
Vol. E104-D  No. 3  pp. 362-369
Type of Manuscript:  Special Section PAPER (Special Section on Foundations of Computer Science — New Trends of Theory of Computation and Algorithm —)
Category: 
Keyword: 
bin packing problemonline algorithmcompetitive analysismathematical optimization
 Summary | Full Text:PDF(456.9KB)

A New Finite Automata Construction Using a Prefix and a Suffix of Regular Expressions
Hiroaki YAMAMOTO Hiroshi FUJIWARA 
Publication:   
Publication Date: 2021/03/01
Vol. E104-D  No. 3  pp. 381-388
Type of Manuscript:  Special Section PAPER (Special Section on Foundations of Computer Science — New Trends of Theory of Computation and Algorithm —)
Category: 
Keyword: 
regular expressionnondeterministic finite automaton
 Summary | Full Text:PDF(285.8KB)

Bounds for the Multislope Ski-Rental Problem
Hiroshi FUJIWARA Kei SHIBUSAWA Kouki YAMAMOTO Hiroaki YAMAMOTO 
Publication:   
Publication Date: 2020/03/01
Vol. E103-D  No. 3  pp. 481-488
Type of Manuscript:  Special Section PAPER (Special Section on Foundations of Computer Science — Frontiers of Theory of Computation and Algorithm —)
Category: 
Keyword: 
online algorithmcompetitive analysisonline optimizationski-rental problems
 Summary | Full Text:PDF(377.6KB)

Competitive Analysis for the 3-Slope Ski-Rental Problem with the Discount Rate
Hiroshi FUJIWARA Shunsuke SATOU Toshihiro FUJITO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2016/06/01
Vol. E99-A  No. 6  pp. 1075-1083
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
online algorithmcompetitive analysisonline optimizationski-rental problems
 Summary | Full Text:PDF(775.9KB)

Online Weight Balancing on the Unit Circle
Hiroshi FUJIWARA Takahiro SEKI Toshihiro FUJITO 
Publication:   IEICE TRANSACTIONS on Information and Systems
Publication Date: 2016/03/01
Vol. E99-D  No. 3  pp. 567-574
Type of Manuscript:  Special Section PAPER (Special Section on Foundations of Computer Science---Developments of the Theory of Algorithms and Computation---)
Category: 
Keyword: 
online algorithmcompetitive analysiscomputational geometryonline optimization
 Summary | Full Text:PDF(378.1KB)

Competitive Analysis for the Flat-Rate Problem
Hiroshi FUJIWARA Atsushi MATSUDA Toshihiro FUJITO 
Publication:   IEICE TRANSACTIONS on Information and Systems
Publication Date: 2016/03/01
Vol. E99-D  No. 3  pp. 559-566
Type of Manuscript:  Special Section PAPER (Special Section on Foundations of Computer Science---Developments of the Theory of Algorithms and Computation---)
Category: 
Keyword: 
online algorithmcompetitive analysisonline optimizationski-rental problems
 Summary | Full Text:PDF(489.8KB)

The Huffman Tree Problem with Unit Step Functions
Hiroshi FUJIWARA Takuya NAKAMURA Toshihiro FUJITO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2015/06/01
Vol. E98-A  No. 6  pp. 1189-1196
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
combinatorial optimizationpolynomial-time algorithmbinary treeoptimal treeHuffman coding
 Summary | Full Text:PDF(642.4KB)

Analysis of Lower Bounds for the Multislope Ski-Rental Problem
Hiroshi FUJIWARA Yasuhiro KONNO Toshihiro FUJITO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2014/06/01
Vol. E97-A  No. 6  pp. 1200-1205
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
online algorithmcompetitive analysisonline optimizationski-rental problems
 Summary | Full Text:PDF(558.8KB)

Collision Probability in an In-Line Equipment Model under Erlang Distribution
Eishi CHIBA Hiroshi FUJIWARA Yoshiyuki SEKIGUCHI Toshihide IBARAKI 
Publication:   IEICE TRANSACTIONS on Information and Systems
Publication Date: 2013/03/01
Vol. E96-D  No. 3  pp. 400-407
Type of Manuscript:  Special Section PAPER (Special Section on Foundations of Computer Science — New Trends in Algorithms and Theory of Computation —)
Category: 
Keyword: 
stochastic modelcollision probabilityErlang distributionclosed formapproximation
 Summary | Full Text:PDF(494.7KB)