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National Institute of Information and Communications Technology, Japan

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6 Papers

Millimetre-wave Electro-Optic Modulator with Quasi-Phase-Matching Array of Orthogonal-Gap-Embedded Patch-antennas on Low-k Dielectric Material

Topic: Microwave Photonics

Authors: Yusuf Nur Wijayanto ¹ , Atsushi Kanno ¹ , Hiroshi Murata ² , Sinya Nakajima ¹ , Tetsuya Kawanishi ¹ and Yasuyuki Okamura ²

Affiliations: ¹ National Institute of Information and Communications Technology, Japan , ² Osaka University, Japan

Digital Object Identifier: 10.5220/0005325200050013

Proceedings of PHOTOPTICS 2015, ISBN: 978-989-758-093-2

Quick Abstract

In Fibre-Wireless (Fi-Wi) links, conversion devices between wireless microwave/ millimetre-wave and lightwave signals are required. In this paper, we propose a wireless millimetre-wave-lightwave signal converter using an electro-optic (EO) modulator with Quasi-Phase-Matching (QPM) array of orthogonal-gap-embedded patch-antennas on a low-k dielectric material. Wireless millimetre-wave signals can be received and converted directly to lightwave signals using the proposed device. It can be operated with no external power supply and extremely-low millimetre-wave losses. The orthogonal-gap-embedded patch-antennas can be used for receiving dual-linearized or circular polarizations of wireless millimetre-wave signals. The QPM array structure can be adopted for enhancing modulation efficiency by transit-time effects consideration. Structure, analysis, and experimental of the proposed device are discussed for 40GHz operational millimetre-wave bands.

Related Ontology Subjects/Areas/Topics (1)

Photonics, Optics and Laser Technology

Constructing Secure-channel Free Searchable Encryption from Anonymous IBE with Partitioned Ciphertext Structure

Topics: Applied Cryptography; Security Protocols

Authors: Keita Emura ¹ and Mohammad Shahriar Rahman ²

Affiliations: ¹ National Institute of Information and Communications Technology (NICT), Japan , ² University of Asia Pacific, Bangladesh

Digital Object Identifier: 10.5220/0004022700840093

Proceedings of SECRYPT 2012/ICETE, ISBN: 978-989-8565-24-2

Quick Abstract

As an extension of public key encryption with keyword search (PEKS), secure channel free PEKS (SCF-PEKS) has been considered. Generic construction of SCF-PEKS (with adaptive security) from strongly existentially unforgeable one-time signature, selective-tag CCA secure tag-based encryption (TBE) and anonymous identity-based encryption (IBE) has been proposed in ISC2011. Since this construction follows the double encryption, where a ciphertext of anonymous IBE is encrypted by TBE, hybrid encryption is applied because usually the ciphertext space of IBE is not equal to the plaintext space of TBE. In this paper, we show that hybrid encryption is not necessary as long as previously-known anonymous IBE schemes are used as a building tool of adaptive SCF-PEKS. Our result leads to a composability of IBE schemes whether they can be applied for constructing adaptive SCF-PEKS or not. Moreover, since we can exclude DEM part, our construction is efficient compared to the original one.

Related Ontology Subjects/Areas/Topics (6)

Applied Cryptography		Data Engineering		Information and Systems Security
Cryptographic Techniques and Key Management		Databases and Data Security		Security Protocols

Flexible Group Key Exchange with On-demand Computation of Subgroup Keys Supporting Subgroup Key Randomization

Topics: Security in Distributed Systems; Applied Cryptography; Authentication; Security Protocols

Authors: Keita Emura ¹ and Takashi Sato ²

Affiliations: ¹ National Institute of Information and Communications Technology (NICT), Japan , ² Japan Advanced Institute of Science and Technology (JAIST), Japan

Digital Object Identifier: 10.5220/0003986003530357

Proceedings of SECRYPT 2012/ICETE, ISBN: 978-989-8565-24-2

Quick Abstract

In AFRICACRYPT2010, Abdalla, Chevalier, Manulis, and Pointcheval proposed an improvement of group key exchange (GKE), denoted by GKE+S, which enables on-demand derivation of independent secret subgroup key for all potential subsets. On-demand derivation is efficient (actually, it requires only one round) compared with GKE for subgroup (which requires two or more rounds, usually) by re-using values which was used for the initial GKE session for superior group. In this paper, we improve the Abdalla et al. GKE+S protocol to support key randomization. In our GKE+S protocol, the subgroup key derivation algorithm is probabilistic, whereas it is deterministic in the original Abdalla et al. GKE+S protocol. All subgroup member can compute the new subgroup key (e.g., for countermeasure of subgroup key leakage) with just one-round additional complexity. Our subgroup key establishment methodology is inspired by the “essential idea” of the NAXOS technique. Our GKE+S protocol is authenticated key exchange (AKE) secure under the Gap Diffie-Hellman assumption in the random oracle model.

Related Ontology Subjects/Areas/Topics (10)

Applied Cryptography	Databases and Data Security	Security in Distributed Systems
Authentication	Information and Systems Security	Security Protocols
Cryptographic Techniques and Key Management	Obstacles	Sensor Networks
Data Engineering

IMPROVING INTERFERENCE IMMUNITY OF SPATIAL EVENT DETECTION SYSTEMUSING ARRAY ANTENNA

Authors: Hiroyuki Tsuji , Miho Koshikawa and Mikio Suzuki

Affiliation: National Institute of Information and Communications Technology (NICT), Japan

Digital Object Identifier: 10.5220/0005414701050111

Proceedings of ICTRS 2012, ISBN: 978-989-8565-28-0

Quick Abstract

This paper proposes new techniques for improving the co-channel interference immunity of the event detection system which realizes indoor event detection scheme. Similar to the conventional methods the signal subspace-based approach sometimes suffers from interference in the same frequency band because the interference signals with different incident angles affect the signal subspace of the received signals at the receiving array antenna. Two types of new event detection methods are proposed to realize immunity against noise and interference in this paper. The first method proposed in this paper exploits the cyclostationarity of communication signals to distinguish the desired signal from the interference and suppresses noise and interfering signals without major hardware design changes. Another approach that improves immunity against co-channel interference is to utilize the transmission control scheme used for personal area network systems. In the proposed method of the study, carrier sense multiple access with collision avoidance (CSMA/CA) technique is utilized to distinguish the desired signal from the other transmitted signals. As a result of the detection of the presence of signals from other stations, the proposed system can avoid the transmitted interference signals from other systems. We are also developing an evaluation equipment to confirm the effectiveness of the proposed approach.

PARACONSISTENT NEGATION AND CLASSICAL NEGATION IN COMPUTATION TREE LOGIC

Topics: Knowledge Representation and Reasoning; Uncertainty in AI ; Model-Based Reasoning

Authors: Norihiro Kamide ¹ and Ken Kaneiwa ²

Affiliations: ¹ Waseda Institute for Advanced Study, Japan , ² National Institute of Information and Communications Technology, Japan

Digital Object Identifier: 10.5220/0002699504640469

Proceedings of ICAART 2010, ISBN: 978-989-674-021-4

Quick Abstract

A paraconsistent computation tree logic, PCTL, is obtained by adding paraconsistent negation to the standard computation tree logic CTL. PCTL can be used to appropriately formalize inconsistency-tolerant temporal reasoning. A theorem for embedding PCTL into CTL is proved. The validity, satisfiability, and model-checking problems of PCTL are shown to be decidable. The embedding and decidability results indicate that we can reuse the existing CTL-based algorithms for validity, satisfiability and model-checking. An illustrative example of medical reasoning involving the use of PCTL is presented.

Related Ontology Subjects/Areas/Topics (5)

Artificial Intelligence		Model-Based Reasoning		Uncertainty in AI
Knowledge Representation and Reasoning		Symbolic Systems

AUTOMATIC PLAYBACK OF 3D BLOG ENTRIES BASED ON 3D VIEWPOINT SIMILARITY

Topics: Searching and Browsing; Multimedia and User Interfaces

Author: Rieko Kadobayashi

Affiliation: National Institute of Information and Communications Technology, Japan

Digital Object Identifier: 10.5220/0001264100180025

Proceedings of WEBIST 2007, ISBN: 978-972-8865-78-8

Quick Abstract

The 3D Blog system allows a user to interact with a 3D model, annotate any spot on the model, and publish the annotations in a blog so that the user can easily communicate with other people and share interests, idea, and questions about 3D models of interest to the user. The main features of the system is that each annotation is saved as a blog entry with 3D viewpoint information, i.e., the user’s viewpoint and view direction as well as 3D information on annotated points. With this 3D viewpoint information, readers of a 3D Blog can reconstruct the exact same 3D scene the blogger saw when reading the blog entry, and, therefore, the readers may understand it better. The system also uses the 3D viewpoint information to detect similar entries and sends trackback links automatically to enable users to easily find people who may have similar interests. Users can easily and intuitively compare the similar entries using the “playback” function which renders the 3D scene in the similar entries. The 3D Blog system is expected to promote emergence of communities of people who share interests and support their communication.

Related Ontology Subjects/Areas/Topics (4)