Showing papers by "NEC published in 2016"

High-Throughput Semi-Honest Secure Three-Party Computation with an Honest Majority

Abstract: In this paper, we describe a new information-theoretic protocol (and a computationally-secure variant) for secure three-party computation with an honest majority. The protocol has very minimal computation and communication; for Boolean circuits, each party sends only a single bit for every AND gate (and nothing is sent for XOR gates). Our protocol is (simulation-based) secure in the presence of semi-honest adversaries, and achieves privacy in the client/server model in the presence of malicious adversaries. On a cluster of three 20-core servers with a 10Gbps connection, the implementation of our protocol carries out over 1.3 million AES computations per second, which involves processing over 7 billion gates per second. In addition, we developed a Kerberos extension that replaces the ticket-granting-ticket encryption on the Key Distribution Center (KDC) in MIT-Kerberos with our protocol, using keys/ passwords that are shared between the servers. This enables the use of Kerberos while protecting passwords. Our implementation is able to support a login storm of over 35,000 logins per second, which suffices even for very large organizations. Our work demonstrates that high-throughput secure computation is possible on standard hardware.

Development and Validation of a Protein-Based Risk Score for Cardiovascular Outcomes Among Patients With Stable Coronary Heart Disease

Abstract: Importance Precise stratification of cardiovascular risk in patients with coronary heart disease (CHD) is needed to inform treatment decisions. Objective To derive and validate a score to predict risk of cardiovascular outcomes among patients with CHD, using large-scale analysis of circulating proteins. Design, Setting, and Participants Prospective cohort study of participants with stable CHD. For the derivation cohort (Heart and Soul study), outpatients from San Francisco were enrolled from 2000 through 2002 and followed up through November 2011 (≤11.1 years). For the validation cohort (HUNT3, a Norwegian population-based study), participants were enrolled from 2006 through 2008 and followed up through April 2012 (5.6 years). Exposures Using modified aptamers, 1130 proteins were measured in plasma samples. Main Outcomes and Measures A 9-protein risk score was derived and validated for 4-year probability of myocardial infarction, stroke, heart failure, and all-cause death. Tests, including the C statistic, were used to assess performance of the 9-protein risk score, which was compared with the Framingham secondary event model, refit to the cohorts in this study. Within-person change in the 9-protein risk score was evaluated in the Heart and Soul study from paired samples collected 4.8 years apart. Results From the derivation cohort, 938 samples were analyzed, participants’ median age at enrollment was 67.0 years, and 82% were men. From the validation cohort, 971 samples were analyzed, participants’ median age at enrollment was 70.2 years, and 72% were men. In the derivation cohort, C statistics were 0.66 for refit Framingham, 0.74 for 9-protein, and 0.75 for refit Framingham plus 9-protein models. In the validation cohort, C statistics were 0.64 for refit Framingham, 0.70 for 9-protein, and 0.71 for refit Framingham plus 9-protein models. Adding the 9-protein risk score to the refit Framingham model increased the C statistic by 0.09 (95% CI, 0.06-0.12) in the derivation cohort, and in the validation cohort, the C statistic was increased by 0.05 (95% CI, 0.02-0.09). Compared with the refit Framingham model, the integrated discrimination index for the 9-protein model was 0.12 (95% CI, 0.08-0.16) in the derivation cohort and 0.08 (95% CI, 0.05-0.10) in the validation cohort. In analysis of paired samples among 139 participants with cardiovascular events after the second sample, absolute within-person annualized risk increased more for the 9-protein model (median, 1.86% [95% CI, 1.15%-2.54%]) than for the refit Framingham model (median, 1.00% [95% CI, 0.87%-1.19%]) (P = .002), while among 375 participants without cardiovascular events, both scores changed less and similarly (P = .30). Conclusions and Relevance Among patients with stable CHD, a risk score based on 9 proteins performed better than the refit Framingham secondary event risk score in predicting cardiovascular events, but still provided only modest discriminative accuracy. Further research is needed to assess whether the score is more accurate in a lower-risk population.

DeBot: Twitter Bot Detection via Warped Correlation

Abstract: We develop a warped correlation finder to identify correlated user accounts in social media websites such as Twitter. The key observation is that humans cannot be highly synchronous for a long duration, thus, highly synchronous user accounts are most likely bots. Existing bot detection methods are mostly supervised, which requires a large amount of labeled data to train, and do not consider cross-user features. In contrast, our bot detection system works on activity correlation without requiring labeled data. We develop a novel lag-sensitive hashing technique to cluster user accounts into correlated sets in near real-time. Our method, named DeBot, detects thousands of bots per day with a 94% precision and generates reports online everyday. In September 2016, DeBot has accumulated about 544,868 unique bots in the previous one year. We compare our detection technique with per-user techniques and with Twitter's suspension system. We observe that some bots can avoid Twitter's suspension mechanism and remain active for months, and, more alarmingly, we show that DeBot detects bots at a rate higher than the rate Twitter is suspending them.

Characteristics and Design of Power Hardware-in-the-Loop Simulations for Electrical Power Systems

Abstract: This paper presents a compendious summary of power hardware-in-the-loop (PHIL) simulations that are used for designing, analyzing, and testing of electrical power system components. PHIL simulations are an advanced application of real-time simulations that represent novel methods, which conjoin software and hardware testing. This contribution outlines necessary requirements for the implementation of PHIL simulations, which are defined by the nature of the digital real-time simulator, the power amplifier, and the power interface (PI). Fundamental characteristics, such as the input/output systems, PI, interface algorithm, and system stability considerations, are discussed for PHIL setups, in order to illustrate both flexibility and complexity of this compound simulation method. The objective of this work is to elaborate an understandable overview of PHIL simulation for electrical power systems and to constitute a contemporary state-of-the-art status of this research area.

Thermoelectric generation based on spin Seebeck effects

Abstract: The spin Seebeck effect (SSE) refers to the generation of a spin current as a result of a temperature gradient in magnetic materials including insulators. The SSE is applicable to thermoelectric generation because the thermally generated spin current can be converted into a charge current via spin-orbit interaction in conductive materials adjacent to the magnets. The insulator-based SSE device exhibits unconventional characteristics potentially useful for thermoelectric applications, such as simple structure, device-design flexibility, and convenient scaling capability. In this article, we review recent studies on the SSE from the viewpoint of thermoelectric applications. Firstly, we introduce the thermoelectric generation process and measurement configuration of the SSE, followed by showing fundamental characteristics of the SSE device. Secondly, a theory of the thermoelectric conversion efficiency of the SSE device is presented, which clarifies the difference between the SSE and conventional thermoelectric effects and the efficiency limit of the SSE device. Finally, we show preliminary demonstrations of the SSE in various device structures for future thermoelectric applications and discuss prospects of the SSE-based thermoelectric technologies.

Multiple Rabi Splittings under Ultrastrong Vibrational Coupling.

Abstract: From the high vibrational dipolar strength offered by molecular liquids, we demonstrate that a molecular vibration can be ultrastrongly coupled to multiple IR cavity modes, with Rabi splittings reaching 24% of the vibration frequencies. As a proof of the ultrastrong coupling regime, our experimental data unambiguously reveal the contributions to the polaritonic dynamics coming from the antiresonant terms in the interaction energy and from the dipolar self-energy of the molecular vibrations themselves. In particular, we measure the opening of a genuine vibrational polaritonic band gap of ca. 60 meV. We also demonstrate that the multimode splitting effect defines a whole vibrational ladder of heavy polaritonic states perfectly resolved. These findings reveal the broad possibilities in the vibrational ultrastrong coupling regime which impact both the optical and the molecular properties of such coupled systems, in particular, in the context of mode-selective chemistry.

Thermoelectric Generation Based on Spin Seebeck Effects

Abstract: The spin Seebeck effect (SSE) refers to the generation of a spin current as a result of a temperature gradient in magnetic materials including insulators The SSE is applicable to thermoelectric generation because the thermally generated spin current can be converted into a charge current via spin-orbit interaction in conductive materials adjacent to the magnets The insulator-based SSE device exhibits unconventional characteristics potentially useful for thermoelectric applications, such as simple structure, device-design flexibility, and convenient scaling capability In this article, we review recent studies on the SSE from the viewpoint of thermoelectric applications Firstly, we introduce the thermoelectric generation process and measurement configuration of the SSE, followed by showing fundamental characteristics of the SSE device Secondly, a theory of the thermoelectric conversion efficiency of the SSE device is presented, which clarifies the difference between the SSE and conventional thermoelectric effects and the efficiency limit of the SSE device Finally, we show preliminary demonstrations of the SSE in various device structures for future thermoelectric applications and discuss prospects of the SSE-based thermoelectric technologies

Availability Modeling and Analysis of a Virtualized System Using Stochastic Reward Nets

Abstract: Availability is one of the key requirements for modern networked system. Availability of a virtualized system can be modelled and analyzed using stochastic models. In our previous work, availability of a virtualized system was modeled using a hierarchical model to incorporate the detailed behavior of virtual machines (VMs)' failure and recovery with respect to the system behavior. In particular, a truncated continuous time Markov chain model was used for VM mode. In this paper, we propose to construct a stochastic reward nets (SRN) to model and analyze the availability of a virtualized system. Further, we study the effect on the availability when restrictions on the guard functions are relaxed. We use a virtualized data center (VDC) using three hosts with a multiple number of VMs on each hosting servers, and we incorporate (i) failure and recovery of hosting servers and VMs, (ii) VM high availability (HA) and (iii) VM live migration (LM). The VDCs with/without using VM HA and LM are compared in terms of capacity oriented availability (i.e., number of available VMs).

Single-photon emission at 1.5 μm from an InAs/InP quantum dot with highly suppressed multi-photon emission probabilities

Abstract: We have demonstrated highly pure single-photon emissions from an InAs/InP quantum dot at the wavelength of 1.5 μm. By applying quasi-resonant excitation, one exciton is deterministically generated in an excited state, which then relaxes to the exciton ground state before recombining to emit a single photon. The photon-correlation function of the emission from the exciton ground state exhibits a record g(2)(0) value of (4.4 ± 0.2) × 10−4 measured using high-performance super-conducting single-photon detectors, without any background subtraction. This single-photon source with extremely low multi-photon emission probability paves the way to realize long distance quantum key distribution and low error-rate quantum computation.

Capacity-approaching transmission over 6375 km at spectral efficiency of 8.3 bit/s/Hz

Abstract: Transmission capacities of 34.9Tb/s over 6375 km based on Gaussian-like DP-64APSK and 33.3 Tb/s over 6800 km using DP-32QAM are demonstrated using hybrid spans with quasi-single-mode fiber. Nonlinear compensation enables 8.3 b/s/Hz spectral efficiency.

Flexible heat-flow sensing sheets based on the longitudinal spin Seebeck effect using one-dimensional spin-current conducting films.

Abstract: Heat-flow sensing is expected to be an important technological component of smart thermal management in the future. Conventionally, the thermoelectric (TE) conversion technique, which is based on the Seebeck effect, has been used to measure a heat flow by converting the flow into electric voltage. However, for ubiquitous heat-flow visualization, thin and flexible sensors with extremely low thermal resistance are highly desired. Recently, another type of TE effect, the longitudinal spin Seebeck effect (LSSE), has aroused great interest because the LSSE potentially offers favourable features for TE applications such as simple thin-film device structures. Here we demonstrate an LSSE-based flexible TE sheet that is especially suitable for a heat-flow sensing application. This TE sheet contained a Ni0.2Zn0.3Fe2.5O4 film which was formed on a flexible plastic sheet using a spray-coating method known as “ferrite plating”. The experimental results suggest that the ferrite-plated film, which has a columnar crystal structure aligned perpendicular to the film plane, functions as a unique one-dimensional spin-current conductor suitable for bendable LSSE-based sensors. This newly developed thin TE sheet may be attached to differently shaped heat sources without obstructing an innate heat flux, paving the way to versatile heat-flow measurements and management.

Optical Switches Based on Silicon Photonics for ROADM Application

Abstract: We demonstrate compact and low-loss $8 \times 8$ silicon photonic switch modules, which are applicable to transponder aggregators (TPAs) in colorless, directionless, and contentionless reconfigurable optical add-drop multiplexers. Newly designed silicon optical switch chips incorporating spot size converters with polarization insensitive and wavelength insensitive properties over C/L bands are packaged. The developed module shows about 6-dB average excess optical loss, including optical coupling loss, on all 64 optical paths with low-polarization-dependent loss and low crosstalk. Using these compact optical switch modules, we construct a TPA prototype featuring over 100-port optical switch subsystem densely mounted on one board and confirm its feasibility.

Analysis of satellite images for disaster detection

Abstract: Analysis of satellite images plays an increasingly vital role in environment and climate monitoring, especially in detecting and managing natural disaster. In this paper, we proposed an automatic disaster detection system by implementing one of the advance deep learning techniques, convolutional neural network (CNN), to analysis satellite images. The neural network consists of 3 convolutional layers, followed by max-pooling layers after each convolutional layer, and 2 fully connected layers. We created our own disaster detection training data patches, which is currently focusing on 2 main disasters in Japan and Thailand: landslide and flood. Each disaster's training data set consists of 30000∼40000 patches and all patches are trained automatically in CNN to extract region where disaster occurred instantaneously. The results reveal accuracy of 80%∼90% for both disaster detection. The results presented here may facilitate improvements in detecting natural disaster efficiently by establishing automatic disaster detection system.

Density Functional Theory Calculations of Lithium Adsorption and Insertion to Defect-Free and Defective Graphene

Abstract: Density functional theory calculations with periodic boundary conditions were performed to clarify the interaction between lithium atoms and a graphene sheet. Three types of graphene sheets—defect-free, containing carbon vacancies VCn (n = 1, 2, 3, 4, 6, 10, 13, 16, and 24), and their hydrogen-terminated carbon vacancies—were examined in this study. We found that a lithium atom inserted into bare carbon vacancy VCn (n ≥ 3) is more stable than that in bulk lithium metal and that it is trapped by the vacancy. On the other hand, a lithium atom inserted into the hydrogen-terminated carbon vacancies is less stable than that in bulk metal. These results suggest that the electrochemical in-plane insertion of lithium ions into the bare carbon vacancies is possible, whereas the insertion into the hydrogen-terminated vacancies is unlikely because the precipitation of lithium metal is energetically more favorable.

Mutation in VPS33A affects metabolism of glycosaminoglycans: a new type of mucopolysaccharidosis with severe systemic symptoms.

Abstract: Mucopolysaccharidoses (MPS) are a group of genetic deficiencies of lysosomal enzymes that catabolize glycosaminoglycans (GAG). Here we describe a novel MPS-like disease caused by a specific mutation in the VPS33A gene. We identified several Yakut patients showing typical manifestations of MPS: coarse facial features, skeletal abnormalities, hepatosplenomegaly, respiratory problems, mental retardation, and excess secretion of urinary GAG. However, these patients could not be diagnosed enzymatically as MPS. They showed extremely high levels of plasma heparan sulphate (HS, one of GAG); 60 times the normal reference range and 6 times that of MPS patients. Additionally, most patients developed heart, kidney, and hematopoietic disorders, which are not typical symptoms for conventional MPS, leading to a fatal outcome between 1 and 2-years old. Using whole exome and Sanger sequencing, we identified homozygous c.1492C > T (p.Arg498Trp) mutations in the VPS33A gene of 13 patients. VPS33A is involved in endocytic and autophagic pathways, but the identified mutation did not affect either of these pathways. Lysosomal over-acidification and HS accumulation were detected in patient-derived and VPS33A-depleted cells, suggesting a novel role of this gene in lysosomal functions. We hence propose a new type of MPS that is not caused by an enzymatic deficiency.

Numerical Simulations of Large-Scale Sediment Transport Caused by the 2011 Tohoku Earthquake Tsunami in Hirota Bay, Southern Sanriku Coast

Abstract: A numerical sediment transport model (STM) was used to investigate coastal geomorphic changes that resulted from the 2011 Tohoku earthquake tsunami in Rikuzentakata City and Hirota Bay on the south...

High-Sensitivity and Broadband, Real-Time Terahertz Camera Incorporating a Micro-Bolometer Array With Resonant Cavity Structure

Abstract: Terahertz (THz) cameras comprising an uncooled micro-bolometer array have been developed for simple THz imaging, and the improvement of their sensitivity is one of the important issues. We fabricated a new micro-bolometer array with a resonant cavity structure for a real-time THz camera, alongside a new method for evaluating the sensitivity across a wide range of the THz frequency region. The frequency dependence of the sensitivity of the THz camera is measured in the 0.5–2.0-THz frequency range taking the polarization dependence into account. It was found that the resonant cavity structure effectively increased the sensitivity of the THz camera, and, actually, the improvement by one order of magnitude was achieved in the frequency range below 1 THz. The THz camera with much enhanced sensitivity will expand the frontiers of real-time THz imaging such as molecular imaging and nondestructive inspection.

Giving Infants an Identity: Fingerprint Sensing and Recognition

Abstract: There is a growing demand for biometrics-based recognition of children for a number of applications, particularly in developing countries where children do not have any form of identification These applications include tracking child vaccination schedules, identifying missing children, preventing fraud in food subsidies, and preventing newborn baby swaps in hospitals Our objective is to develop a fingerprint-based identification system for infants (age range: 0-12 months)1 Our ongoing research has addressed the following issues: (i) design of a compact, comfortable, high-resolution (>1,000 ppi) fingerprint reader; (ii) image enhancement algorithms to improve quality of infant fingerprint images; and (iii) collection of longitudinal infant fingerprint data to evaluate identification accuracy over time This collaboration between Michigan State University, Dayalbagh Educational Institute, Saran Ashram Hospital, Agra, India and NEC Corporation, has demonstrated the feasibility of recognizing infants older than 4 weeks using fingerprints

Acoustic event detection based on non-negative matrix factorization with mixtures of local dictionaries and activation aggregation

Abstract: This paper proposes a new non-negative matrix factorization (NMF) based acoustic event detection (AED) method with mixtures of local dictionaries (MLD) and activation aggregation. One of the key problems of conventional NMF-based methods is instability of activations due to redundancy of a region spanned by the bases of dictionaries. Sounds inside the redundant region are often decomposed into undesired combinations of bases and activations that cause failure of detection. The proposed method employs MLD for allocating sub-groups of basis dictionaries to acoustic elements to minimize redundancy in the region and obtain controlled activations. In order to make activations more stable, the proposed method also introduces activation aggregation which combines basis-wise activations into acoustic-element-wise activations. Much more stable activations by the proposed method lead to significant improvement in F-measure by up to 60% compared to an ordinary convolutive-NMF-based method. The proposed method also outperforms a latest alternative which is not based on NMF.

Method for controlling access to a shared resource

Abstract: A method for controlling access to a shared resource for a plurality of collaborative users includes securely providing, on a storage and device entity, the shared resource. The shared resource is created by a resource owner entity. The method further includes specifying access control rules for the shared resource, translating the access control rules into a smart contract, including the smart contract into a blockchain, and if a second user requests access to the shared resource, performing access decisions for the shared resource by evaluating the smart contract with regard to the access control rules.

Simple Distributed Scheduling With Collision Detection in TSCH Networks

Abstract: The IETF IPv6 over the time synchronized channel hopping mode of IEEE 802.15.4e (6TiSCH) working group standardizes a distributed mechanism for neighbor motes to agree on a schedule to communicate, driven by a scheduling function. This letter introduces the notion of housekeeping to the schedule function, in which motes relocate cells in the schedule to build a collision-free schedule in a distribute manner. The solution, based on detecting underperforming cells and listening for unexpected packets, does not require additional signaling traffic or state. This letter shows that simple housekeeping rules introduced allow a network to contain 17% more motes and suffer from 64% fewer collision, while maintaining end-to-end reliability above 99.5% in a typical industrial environment. This solution is now being discussed for standardization at 6TiSCH.

SDNsec: Forwarding Accountability for the SDN Data Plane

Abstract: SDN promises to make networks more flexible, programmable, and easier to manage. Inherent security problems in SDN today, however, pose a threat to the promised benefits. First, the network operator lacks tools to proactively ensure that policies will be followed or to reactively inspect the behavior of the network. Second, the distributed nature of state updates at the data plane leads to inconsistent network behavior during reconfigurations. Third, the large flow space makes the data plane susceptible to state exhaustion attacks. This paper presents SDNsec, an SDN security extension that provides forwarding accountability for the SDN data plane. Forwarding rules are encoded in the packet, ensuring consistent network behavior during reconfigurations and limiting state exhaustion attacks due to table lookups. Symmetric-key cryptography is used to protect the integrity of the forwarding rules and enforce them at each switch. A complementary path validation mechanism allows the controller to reactively examine the actual path taken by the packets. Furthermore, we present mechanisms for secure link-failure recovery.

System for controlling switch devices, and device and method for controlling system configuration

Abstract: A control device which controls configuration of a control system including a plurality of control nodes, wherein at least one control node controls a plurality of switch devices by sending packet handling rules, includes: a monitor which monitors workloads of control nodes in use, each control node in use controlling at least one switch device; and a controller which changes count of control nodes in use based on workload information monitored.

Large-scale, high-speed tsunami prediction for the Great Nankai Trough Earthquake on the K computer

Abstract: We improved the tsunami simulation code JAGURS, which is a paralleled version of URSGA code for a large-scale, high-speed tsunami prediction in the Nankai trough, Japan. We optimized the loop kernel for velocity update and intergrid communication on a three-dimensional torus network. Linear scaling was achieved up to the full system capability of the K computer 82,944 nodes in a strong scaling test that used 100 billion finite-difference grid points. The measured performance on the K computer was 1.2 petaflops 11.5% of peak speed. Intergrid communication was optimized for a three-nested-grid model consisting of 0.68 billion grid points. Grid spacing in the area with the finest grid 180 km × 120 km was about 5 m. We successfully implemented a large-scale tsunami simulation using this model that ran in about 30% of real time. We believe that this is the fastest tsunami prediction achieved to date with such a large-scale model. Our code can provide high-resolution tsunami prediction for broad regions within a reasonable time to assist emergency rescue and relief operations during future devastating tsunamis comparable to the 2004 Sumatra, 2010 Chile, and 2011 Tohoku tsunamis.

Emerging transport SDN architecture and use cases

Abstract: SDN and virtualization promise to simplify transport network control, while adding management flexibility and allowing the rapid development of new services by enabling programmatic control of transport networks and equipment. A consensus transport SDN (T-SDN) architecture using standards- based system inter-component interfaces further enables flexible composition of functionally unified systems from among vendor-diverse software and hardware components. In this article we discuss the high-level reference T-SDN architecture emerging from early experience, standards, and related industry activities, with attention paid to critical standards-based system interface methodologies. We examine key T-SDN use cases including service bandwidth on demand, virtual transport network services, and multi-layer control convergence and resource optimization.

Direct imaging of isofrequency contours in photonic structures

Abstract: The isofrequency contours of a photonic crystal are important for predicting and understanding exotic optical phenomena that are not apparent from high-symmetry band structure visualizations. We demonstrate a method to directly visualize the isofrequency contours of high-quality photonic crystal slabs that show quantitatively good agreement with numerical results throughout the visible spectrum. Our technique relies on resonance-enhanced photon scattering from generic fabrication disorder and surface roughness, so it can be applied to general photonic and plasmonic crystals or even quasi-crystals. We also present an analytical model of the scattering process, which explains the observation of isofrequency contours in our technique. Furthermore, the isofrequency contours provide information about the characteristics of the disorder and therefore serve as a feedback tool to improve fabrication processes.

Method and system for byzantine fault-tolerance replicating of data on a plurality of servers

Abstract: A method for byzantine fault-tolerant replication of data on a plurality of n servers by a client, wherein the n servers include one primary node (PN) and n−1 replica nodes (REPN), wherein f servers may arbitrarily fail, and wherein all n servers include a trusted computing entity (TCE), includes: performing a request procedure, performing a prepare procedure, performing a commit procedure, and performing a reply procedure. The request procedure includes providing a request message for requesting a certain operation, and transmitting the request message to all n servers. The prepare procedure includes computing a prepare message including at least part of the content of the request message and a unique identifier (UI), the UI being computed by the TCE, the UI being based on a cryptographic signature of the request message and a unique, monotonic, sequential counter (UMSC), and providing the prepare message to the REPN.

A Versatile Approach for Solving PnP, PnPf, and PnPfr Problems

Abstract: This paper proposes a versatile approach for solving three kinds of absolute camera pose estimation problem: PnP problem for calibrated cameras, PnPf problem for cameras with unknown focal length, and PnPfr problem for cameras with unknown focal length and unknown radial distortion. This is not only the first least squares solution to PnPfr problem, but also the first approach formulating three problems in the same theoretical manner. We show that all problems have a common subproblem represented as multivariate polynomial equations. Solving these equations by Grobner basis method, we derive a linear form for the remaining parameters of each problem. Finally, we apply root polishing to strictly satisfy the original KKT condition. The proposed PnP and PnPf solvers have comparable performance to the state-of-the-art methods on synthetic distortion-free data. Moreover, the novel PnPfr solver gives the best result on distorted point data and demonstrates real image rectification against significant distortion.

Wireless D-band communication up to 60 Gbit/s with 64QAM using GaAs HEMT technology

Abstract: Over 40-Gbps wireless communication in the D-band is described. 120-GHz-band transmitter and receiver modules employing direct modulation architecture are developed using 70-nm mHEMT technology for a RF amplifier and 0.1-μm pHEMT technology for an IQ modulator and a frequency doubler. The developed modules successfully demonstrate 64QAM transmission with a data rate of 42 Gbit/s occupying a bandwidth of less than 10 GHz (spectrum efficiency of 4.92 bit/s/Hz) and a BER of less than 10−3. The feasibility of 60 Gbps wireless transmission is also verified. To the best of our knowledge, this is the first time that over 40-Gbps D-band communication using a practical bandwidth of less than 10 GHz is achieved.