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Shiranaga H.,Information and Communications Laboratories | Yamada M.,Information and Communications Laboratories | Urayama H.,Information and Communications Laboratories | Ogawa S.,Information and Communications Laboratories
SEI Technical Review | Year: 2011

The Japanese government has planned to operate a new radio communication system for improving vehicle safety. In this system, on-car units send packets including information of their location and speed using the Carrier Sense Multiple Access (CSMA) method. However, when radio wave sent by a unit is blocked by a building and the unit cannot be detected by others, two or more units can send their packets nearly simultaneously. This can cause a packet collision called "hidden terminal problem," leading to a serious defect in the new ITS (Intelligent Transport System) radio communication system. The authors have developed a new method for improving the receiving rate of packets when the collision occurs by selectively receiving a packet with a stronger power level, and have successfully verified the performance in a field experiment.


Tsukashima K.,Transmission Device R and D Laboratories | Kubota M.,Transmission Device R and D Laboratories | Baba O.,Transmission Device R and D Laboratories | Tango H.,Information and Communications Laboratories | And 3 more authors.
SEI Technical Review | Year: 2011

This paper describes the cost effective 77 GHz transmitter and receiver MMIC (monolithic microwave integrated circuit) that uses a three-dimensional MMIC technology optimized for flip-chip implementation. The MMIC structure incorporates inverse TFMS lines so that a ground metal can be applied to cover the whole chip surface except for interconnect pads. Four metal layers, each of them are covered with polyimide and SiN films. Hence, these MMIC chips require no package, and can be directly assembled on a printed circuit board. The transmitter MMIC is composed of an ×8 multiplier chain (9.5 GHz/38 GHz MLT, 38 GHz AMP, and 38 GHz/76 GHz MLT), and a driver + power amplifier. A saturated output power of 14 dBm has been obtained between 76 and 77 GHz from this transmitter MMIC. A portion of the 38 GHz amplifier output is split for the receiver mixer. The receiver MMIC is composed of multi LNA + MIX blocks and a common ×2 multiplier block that provides a 10 dBm of local oscillator power. A receiver gain of 10 dB and a noise figure of 7.8 dB for a baseband frequency at 10 MHz have been obtained. The die size of the transmitter is 1.5 mm × 2.0 mm and the chip area of the receiver is 1.9 mm × 1.3 mm.


Morita T.,Information and Communications Laboratories
SEI Technical Review | Year: 2011

The performance of spatial interpolation system for traffic conditions by Floating Car Data (FCD) can be improved. This system includes estimation and learning agents, which are assigned to all the road links. Estimation agents renew the Normalized Congestion Level (NCL) for each road link, and learning agents renew the weight values for estimation. The weight values can be calculated by a data mining method. Estimation and learning agents alternately calculate the results to improve the interpolation accuracy. The Coefficient of Determination (CD) and Mean Square Error (MSE) are used to evaluate the interpolation accuracy. The obtained FCD is stored in a learning database. A hard disk drivebased learning database is changed into a memory-based one to improve the performance. The processing time is reduced to 1/30, when the memory-based learning database is used. The average standard deviation of the estimated velocity error is 7.34 km/h in the evaluation area.


Ogiuchi Y.,Information and Communications Laboratories | Higashikubo M.,Information and Communications Laboratories | Nishida K.,Japan National Institute of Advanced Industrial Science and Technology | Kurita T.,Hiroshima University
SEI Technical Review | Year: 2010

Driving Safety Support Systems (DSSS) provide drivers with visual information on their surrounding traffic environment to alert them of possible driving-related dangers, preventing traffic accidents. The image processing sensors installed on the road for the systems need high reliability in tracking vehicles regardless of the environmental conditions. The authors have developed a tracking algorithm with high accuracy and stability even in adverse lighting or weather conditions. This paper outlines the developed algorithm along with the results of public-road testing.


Morita T.,Information and Communications Laboratories | Yano J.,Information and Communications Laboratories | Kagawa K.,Information and Communications Laboratories
SEI Technical Review | Year: 2010

We propose a multi-agent based interpolation system for traffic condition, which includes estimation and learning agents. These agents are assigned to all the road links. Estimation agents renew the velocity of each road link, and learning agents renew the weight values for estimation. Estimation and learning agents alternately calculate the results to improve the interpolation accuracy. The standard deviation of the estimated velocity is 8.53 km/h, which is obtained from the probe car data from 01/11/2007 to 31/10/2008.


Kato T.,Sumitomo Electric | Tanaka K.,Sumitomo Electric | Asada M.,Sumitomo Electric | Yasuhara H.,Sumitomo Electric | And 5 more authors.
SEI Technical Review | Year: 2012

In Japan, automatic license plate recognition systems have been used for more than ten years for measuring the vehicle travel time and other applications that require detailed plate information. To better respond to the requirements in these applications, we have developed an automatic license plate recognition device that features a high recognition rate, low error rate, compact design, high reliability, and low running and installation costs by incorporating innovations in both software and hardware such as new image-processing algorithms, an advanced camera unit, and an imageprocessing board. Drawing on this technology, we are currently working on the development of recognition systems for foreign license plates.


Daido F.,Information and Communications Laboratories | Yoshimura A.,Information and Communications Laboratories | Kouyama S.,Information and Communications Laboratories | Nishioka S.,Information and Communications Laboratories
SEI Technical Review | Year: 2012

GE-PON (Gigabit Ethernet Passive Optical Network) systems have been widely used for broadband access services. As next generation technology of GE-PON, IEEE (Institute of Electrical and Electronics Engineers) 802.3 Working Group standardized the 10G-EPON in 2009 to provide Physical layer and Datalink layer specifications, and IEEE P1904.1 (SIEPON: Service Interoperability in Ethernet Passive Optical Networks) Working Group has been working on the standardization of upper layer protocols to improve service levels and multi-vendor interoperability for GE-PON and 10G-EPON. Along with the standardization activities, the authors have developed communication LSI for 10G-EPON, and verified its technical feasibility and conformity to the SIEPON Standard.


Ogiuchi Y.,Information and Communications Laboratories | Higashikubo M.,Information and Communications Laboratories
SEI Technical Review | Year: 2012

Conventional license plate detection methods have a good success rate in detecting one or a few fixed formats, however, they may fail in some cases such as motorcycles in Japan and foreign vehicles across national borders. The authors have developed a novel method to detect different types of license plates. This method employs Bag-of- Features based on Histogram of Oriented Gradients, which enables the detector to identify characters' common curves on different types of plates. Moreover, this method reduces the computation time and false detection as used in combination with screening technology and edge distribution. The experiment results show that the method is effective for detecting motorcycle license plates in Japan.


Maehata T.,Information and Communications Laboratories | Totani K.,Information and Communications Laboratories | Asaina T.,Information and Communications Laboratories | Tachibana H.,Sumitomo Electric
SEI Technical Review | Year: 2013

In wireless communication, there has been a growing demand for high-speed and high-quality data transmission, particularly since the advent of smartphones. To meet these requirements, multiple-input and multiple-output (MIMO) technology and array antenna systems have been developed. Meanwhile, wireless systems are increasingly being integrated for improved communication performance. To this end, we have developed a 1-bit digital radio frequency (DRF) transmitter using a bandpass delta sigma modulator. This modulator directly transmits wireless signals without an RF circuit, and is therefore expected to reduce the size and power consumption of transmitters according to Moore's Law. Our prototype 1-bit DRF transmitter achieved a high adjacent channel leakage ratio of about 60 dB.


Watanabe K.,Information and Communications Laboratories | Umemura M.,Information and Communications Laboratories | Higashikubo M.,Information and Communications Laboratories
SEI Technical Review | Year: 2013

Information communication technology has been widely used for crime prevention and protection of the elderly. Currently, there is an increasing demand for video surveillance systems that can detect and report a suspicious individual or abnormal behavior. Therefore, we have developed a video surveillance device that detects and tracks persons from video sequences by using filtering logics and reports the results to the user through a network. This paper outlines the video surveillance device and its detection performance.

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