It is impossible to observe the Global Positioning System (GPS) signal traveling in Line of Sight (LOS) indoors. When the position is estimated by using Non-LOS GPS received signals, it results in serious positioning error because the conventional estimation method by the GPS supposes the GPS signals in LOS. However, we may observe reflected signals from the GPS satellites even if indoors. Thus, we consider that the reflected received signals are useful for a reference of the position estimation although it is impossible to directly estimate the position. Supposing that the Received Signal Strength Indicator (RSSI) of the GPS signal varies between locations, we create a database of the RSSI of the GPS signal in each location such as the well-known fingerprinting method. It is possible to estimate the user location by querying the database even if indoors. By experiments, we evaluate the proposed method and propose a shrink method for the database additionally. We show that the proposed method can estimate indoor location well enough.

In this paper, we present an outline of the new Information Delivery System During a Major Disaster for People Who are Deaf (IDDD) designed using a web platform such as node.js and GCM (Google Cloud Message), and explain the performance measurement results. Especially, a new implementation method using web system for embedded system and M2M system is explained. Also, we explained delay to provide disaster information to a user and spreading that information to multiple displays are shorter than previous IDDD.

In this paper, we present the development of an intuitive user interface for hand-held multi-DOF forceps for laparoscopic surgery. Interface design is crucial to the development of hand-held medical instruments. Surgeons may not use medical devices owing to their poor usability, regardless of their performance. In addition, most surgeons do not have the time to learn the use of robotic instruments. We have listed all possible input mechanisms based on the motions of the fingers, and we have designed sample interfaces consisting of effective input mechanisms. The usability of the designed interfaces was evaluated by surgeons via experiments performed using the sample interfaces and a simulator. In summary, we propose a method for designing the most intuitive user interface for hand-held multi-DOF forceps.

Peer-to-peer (P2P) networks use diverse connectivity between participants in networks. P2P networks are useful for many purposes. Sharing content files containing audio, video, data or anything in digital format is very common, and real-time data, such as telephony traffic, is also passed using P2P technology. Because the P2P communication model differs from that of conventional server and client system, further security threats emerge, which are not applicable to server and client architecture. The Telecommunication Standardization Sector (ITU-T) developed network security Recommendations for P2P telecommunications on behalf of the International Telecommunication Union (ITU). This paper provides general survey of the Recommendations.

Telecommunications are powerful tools to reduce loss of life and property damage during disasters. Especially, for the people with disabilities, information provided through their own telecommunication devices is indispensable to move to a place of refuge safely and rapidly. In this paper, we propose the wireless system to send information on disasters to people with disabilities (especially deaf people) and to identify their location at the refuge when they are evacuated. The system consists of cellular phone, web server and electronic display, which are concatenated by Short Message Service (SMS) and Bluetooth. By using these devices and public network services, the system provides a function to send appropriate information to people with disabilities rapidly. The system provides the network platform to share information about their whereabouts with related persons. Finally, we summarize results from demonstration of our system to the deaf people experienced large earthquake.

In performance evaluations of wireless ad hoc networks, both successful data reception and carrier detection probabilities are assumed to be 1 within a circle with certain radius and 0 outside the circle. In real systems, however, those probabilities are gradually changes from 1 to 0 as the distance between a terminal and access point increases. In this paper, we evaluate the throughput of wireless ad hoc networks assuming successful data reception and carrier detection probabilities to be continuous functions of the distance between a terminal and access point. We also show that new additional factors which decrease the throughput will appear under these assumptions, compared to the case where only probabilities 1 and 0 are assumed

In this paper, an iterative detection scheme of precoded OFDM is proposed. The proposed scheme recovers the precoded data symbols correspond to the carriers whose reception powers are degraded by frequency selective fading by using the data symbols after decision and the data symbols are detected again using the recovered precoded data symbols. As the result of numerical analysis, it is confirmed that better performance under severe frequency selective fading channels can be achieved by iteratively repeating the proposed scheme

In OFDM transmission, a loss of sub-carrier orthogonality due to Doppler-spread of the channel leads to inter-carrier interference (ICI). We have proposed a method to reduce the ICI caused by the Doppler spread of the channel. The transmission channel is modeled by a combination of multiple Doppler-shifted propagation paths, and their parameters such as attenuation, relative delay and Doppler-shift are estimated using scattered pilot symbols. The ICI is canceled by multiplying the inverse matrix of the estimated channel matrix with the received OFDM symbol vector. However, the ICI canceller causes enhancement of noise component, so it can't improve the bit error rate characteristics sufficiently. In this paper, we propose the new ICI canceller based on MMSE, which does not cause enhancement of noise component. As the result of computer simulation, it was confirmed that the ICI canceller based on MMSE could reduce the bit error rate more than ICI canceller based on zero-forcing under the Doppler-spread channel.

An 8:1 multiplexer (MUX) and a 1:8 demultiplexer (DEMUX) for 2.4-Gb/s optical communication systems have been developed using 0.35-/spl mu/m GaAs heterojunction field-effect transistors (FETs). To ensure timing margins, a new timing generator with latches and new clock buffers with cross-coupled inverters have been developed. These large-scale integrations (LSIs) operate at over 2.4 Gb/s with a power consumption of 150 mW (MUX) and 170 mW (DEMUX) at a supply voltage of 0.7 V, and at over 5 Gb/s with power consumption of 200 mW at a supply voltage of 0.8 V.