Institution
NEC
Company•Tokyo, Japan•
About: NEC is a company organization based out in Tokyo, Japan. It is known for research contribution in the topics: Signal & Layer (electronics). The organization has 33269 authors who have published 57670 publications receiving 835952 citations. The organization is also known as: NEC Corporation & NEC Electronics Corporation.
Topics: Signal, Layer (electronics), Terminal (electronics), Transmission (telecommunications), Electrode
Papers published on a yearly basis
Papers
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TL;DR: A large population of mobile stations that are interconnected by a multihop wireless network is considered, with the need to support multimedia communications, with low latency requirements for interactive traffic and quality-of-service (QoS) support for real-time streams (voice/video).
Abstract: We consider a large population of mobile stations that are interconnected by a multihop wireless network. The applications of this wireless infrastructure range from ad hoc networking (e.g., collaborative, distributed computing) to disaster recovery (e.g., fire, flood, earthquake), law enforcement (e.g., crowd control, search-and-rescue), and military (automated battlefield). Key characteristics of this system are the large number of users, their mobility, and the need to operate without the support of a fixed (wired or wireless) infrastructure. The last feature sets this system apart from existing cellular systems and in fact makes its design much more challenging. In this environment, we investigate routing strategies that scale well to large populations and can handle mobility. In addition, we address the need to support multimedia communications, with low latency requirements for interactive traffic and quality-of-service (QoS) support for real-time streams (voice/video). In the wireless routing area, several schemes have already been proposed and implemented (e.g., hierarchical routing, on-demand routing, etc.). We introduce two new schemes-fisheye state routing (FSR) and hierarchical state routing (HSR)-which offer some competitive advantages over the existing schemes. We compare the performance of existing and proposed schemes via simulation.
768 citations
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NEC1
TL;DR: In this paper, the authors present microscopic total energy calculations which provide a cohesive property and electronic structures of a new form of solid carbon, the face-centered-cubic crystal (fcc ${\mathrm{C}}_{60}$).
Abstract: We present microscopic total-energy calculations which provide a cohesive property and electronic structures of a new form of solid carbon, the face-centered-cubic ${\mathrm{C}}_{60}$ crystal (fcc ${\mathrm{C}}_{60}$). We find that ${\mathrm{C}}_{60}$ clusters are condensed by van der Waals force, and that the resulting fcc ${\mathrm{O}}_{60}$ is a novel semiconductor with direct energy gap of 1.5 eV at the Brillouin-zone boundary (X point). We also find that an ``impurity'' ${\mathrm{C}}_{60}$K cluster induces a shallow donor state in fcc ${\mathrm{C}}_{60}$.
768 citations
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NEC1
TL;DR: In this paper, the authors provided a low-cost semiconductor device that commercial and quality-assured (inspected) chip size packages can be stacked and has a small co-planarity value and a high mounting reliability.
Abstract: There is provided a low-cost semiconductor device that commercial and quality-assured (inspected) chip size packages can be stacked and has a small co-planarity value and a high mounting reliability. A semiconductor device in which a flexible circuit substrate is adhered to at least a part of a lateral side of a semiconductor package, and the flexible circuit substrate, which is on a side facing solder balls of the semiconductor package, is folded at a region inside of an edge of the semiconductor package (FIG. 1).
752 citations
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TL;DR: In this article, self-determining collimated light is generated in a photonic crystal fabricated on silicon and the divergence of the collimated beam is insensitive to that of the incident beam and much smaller than the divergence generated in conventional Gaussian optics.
Abstract: We found that self-determining collimated light is generated in a photonic crystal fabricated on silicon. The divergence of the collimated beam is insensitive to that of the incident beam and much smaller than the divergence that would be generated in conventional Gaussian optics. The incident-angle dependence of the self-collimated light propagation including lens-like divergent propagation was interpreted in terms of the highly modulated dispersion surfaces with inflection points, where the curvature changes from downward to upward corresponding to respectively a concave/convex-lens case. This demonstration is an important step towards controlling beam profile in photonic crystal integrated light circuits and towards developing “photonic crystalline optics.”
717 citations
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TL;DR: It is shown that the watermark is robust to rotation, scale, and translation, and tests examining the watermarks resistance to cropping and JPEG compression.
Abstract: Many electronic watermarks for still images and video content are sensitive to geometric distortions. For example, simple rotation, scaling, and/or translation (RST) of an image can prevent blind detection of a public watermark. In this paper, we propose a watermarking algorithm that is robust to RST distortions. The watermark is embedded into a one-dimensional (1-D) signal obtained by taking the Fourier transform of the image, resampling the Fourier magnitudes into log-polar coordinates, and then summing a function of those magnitudes along the log-radius axis. Rotation of the image results in a cyclical shift of the extracted signal. Scaling of the image results in amplification of the extracted signal, and translation of the image has no effect on the extracted signal. We can therefore compensate for rotation with a simple search, and compensate for scaling by using the correlation coefficient as the detection measure. False positive results on a database of 10 000 images are reported. Robustness results on a database of 2000 images are described. It is shown that the watermark is robust to rotation, scale, and translation. In addition, we describe tests examining the watermarks resistance to cropping and JPEG compression.
714 citations
Authors
Showing all 33297 results
Name | H-index | Papers | Citations |
---|---|---|---|
Pulickel M. Ajayan | 176 | 1223 | 136241 |
Xiaodong Wang | 135 | 1573 | 117552 |
S. Shankar Sastry | 122 | 858 | 86155 |
Sumio Iijima | 106 | 633 | 101834 |
Thomas W. Ebbesen | 99 | 305 | 70789 |
Kishor S. Trivedi | 95 | 698 | 36816 |
Sharad Malik | 95 | 615 | 37258 |
Shigeo Ohno | 91 | 303 | 28104 |
Adrian Perrig | 89 | 374 | 53367 |
Jan M. Rabaey | 81 | 525 | 36523 |
C. Lee Giles | 80 | 536 | 25636 |
Edward A. Lee | 78 | 462 | 34620 |
Otto Zhou | 74 | 322 | 18968 |
Katsumi Kaneko | 74 | 581 | 28619 |
Guido Groeseneken | 73 | 1074 | 26977 |