In this paper, we propose a passive and contactless epidermal pressure sensor patch printed on a paper substrate with silver nano-particle ink. This disposable patch can be used to measure the pressure between the clothes and the human body. Different from the conventional pressure sensors, the pressure can be measured wirelessly without disturbing the motion of the users. The sensor circuit pattern is printed by a conductive inkjet printer and the sensor's pressure value is detected by a reader coil through the change of the capacitance of an LC resonant circuit. We propose a sensor design method that minimizes the effect of the human body. We demonstrate our sensor patch by measuring the pressure exerted by compression garments whose pressure distribution is important for the wearer's health.

This paper proposes selective compressed sensing, an extension of the conventional compressed sensing that effectively compresses the frequency band(s) of interest while maintaining a backward compatibility with the compressed sensing. We exploit the fact that several sensing applications are interested in analyzing specific frequency bands only. In contrast to most conventional researches that use a random matrix as a measurement matrix, we present an optimized measurement matrix using the Walsh-Hadamard matrix and demonstrate that our selective compressed sensing method can reduce the amount of sensing data required to be transmitted. Compressed sensing can reconstruct all frequencies evenly from the raw data; the accuracy of the reconstructed data is primarily determined by the sparsity of the measurement signal. However, the compression process in the proposed selective compressed sensing method bypasses the calculation of unnecessary Fourier frequency band signals during the measurement. To reduce computational instructions and enable real-time compression by the resource-constrained microprocessors, we introduce two new techniques: the measurement matrix separations and the fast Walsh-Hadamard transform (FWHT) sorted by sequency. We demonstrate that this compression algorithm can reduce the number of instructions to approximately 1/512 of that of the compressed sensing to extract 40% of the whole spectrum from the raw data, when the data chunk size is 4096 bytes.

Information leakages are one of the main security threats in today's Internet. As ICN is expected to become the core architecture for Future Internet, it is therefore mandatory to prevent this threat. This paper proves that some ICN configuration prevents information leakages via Data packets and shows that it is an open problem to prevent interest packets from carrying encoded crucial information in their names. Assuming that names in ICN will follow the current URL format commonly used in the Internet, we get the statistics of web URL based on extensive crawling experiments of main internet organizations. Then we propose a simple filtering technique based on these statistics for firewall to detect anomalous names in ICN. The experiment shows that our filtering technique recognizes 15% of names in our dataset as malicious. As the false positive rate is still high for this filter to be used in a real world operation, this work is an important step for detecting anomalous names and preventing information-leakage in ICN.

In the aftermath of natural disasters (e.g., earthquakes and hurricanes), information dissemination to and from citizens and authorities often involves the use of mobile network services. They may do so to seek help, distribute critical information, and possibly to confirm the safety of relatives and friends. The traffic on the cellular network typically increases substantially in the aftermath of such disasters. The situation is further compounded by disruptions caused by damage to the network infrastructure and the non-availability of power. Networks are fragmented, and communication is intermittent and disruption prone. In this paper, we propose a name-based many-to-many communication service for such fragmented networks. The key feature of this service is an integration of several communication methods, such as push-based and pull-based. The service effectively supports a variety of network situations by leveraging the features of information-centric networks.

Instant Inkjet Circuits by silver nano-particle ink realized home-brew electric circuit fabrication. However, current method can support only single-layered patterns, and conventional inter-layer connection methods are not suitable. In this paper, we will evaluate various easy-to-use inter-layer connection methods by making via holes, especially the ones made by different drilling mechanisms. We show that the felting needle is the best candidate as it can establish good conductivity immediately after nano-particle ink is printed into the hole, without using any curing process.

According to the statistics, people upgrade smartphones at every two years, which means tremendous number of phones will be left unused. In this paper, we propose a method to use Android-based smartphones as wireless sensors for environmental monitoring. Although the idea of using smartphones as a wireless sensor sounds naive, the previous approaches were un-practical because of its limited battery life. In this paper, we exploit the Linux kernel boot mode on Android devices to extend the battery life drastically. Unlike normal mode, power consumption in the kernel mode is minimum but still it is possible to access to all the sensors in principle. In this paper, we measure the power consumption of Nexus5 while booting, running and shutting down Android OS / Linux kernel and estimate the battery life assuming a duty cycle. The results show that utilizing the Linux kernel can extend the battery life up to 10.9 times when the sensing interval is 3 minutes.

Wireless LAN multicast is a suitable mechanism for multimedia streaming because of its bandwidth efficiency. However, wireless multicast has several problems in terms of power efficiency. In this study, we analyze the power efficiency of multicast in IEEE 802.11 networks and show that multicast increases the power consumption of clients significantly irrespective of whether the clients join multicast groups or not. The main reason is that IP multicast packets are transferred as broadcast frames in IEEE 802.11 networks. To improve power efficiency, we propose a new multicast streaming mechanism. Our work is strongly motivated by Flexible Multicast Service (FMS), which is a new IEEE 802.11 standard. FMS permits access points (APs) to transmit multicast frames in more than one delivery traffic indication message (DTIM) interval, which allows clients to wake up at alternate DTIM intervals, rather than every DTIM. However, our analysis proved that FMS is not an optimal mechanism in terms of power efficiency. We propose a new mechanism that provides more power-efficient multicast multimedia streaming, without delay or throughput penalty. Our method focuses on how to reduce the number of unnecessary frames received by clients. The key idea is to stagger the transmission timing to let clients avoid receiving unnecessary frames. We evaluate the mechanism by comprehensive analysis and simulations. The results show that the mechanism achieves significant power savings in wireless LAN multicast networks.

Pedestrians have difficulty noticing hybrid vehicles (HVs) and electrical vehicles (EVs) quietly approaching from behind. We propose a vehicle detection scheme using a smartphone carried by a pedestrian. A notification of a vehicle approaching can be delivered to wearable devices such as Google Glass. We exploit the high-frequency switching noise generated by the motor unit in HVs and EVs. Although people are less sensitive to these high-frequency ranges, these sounds are prominent even on a busy street, and it is possible for a smartphone to detect these signals. The ambient sound captured at 48 kHz is converted to a feature vector in the frequency domain. A J48 classifier implemented on a smartphone can determine whether an EV or HV is approaching. We have collected a large amount of vehicle data at various locations. The false-positive and false-negative rates of our detection scheme are 1.2% and 4.95%, respectively. The first alarm was detected as early as 11.6 s before the vehicle approached the observer. The scheme can also determine the vehicle speed and vehicle type.

In this paper, we considered the possibility of using electricity harvested from the microwave field leaked from commercial microwave ovens. Our experimental results showed that the leakage received by a dipole antenna was about 0 dBm (1 mW) at a point 5 cm in front of the door. A rectenna consisting of a dipole antenna and charge pump can convert the leaked microwave energy into a DC current. When a microwave oven is operated for 2 min, 9.98 mJ of energy was harvested. We demonstrated that this energy is sufficient for powering a digital cooking timer to count down for 3 min and beep for 2.5 s. The operation of other kitchen devices was also demonstrated.

In this poster, we propose an authentication system, especially registration procedure, that can be used before and after a disaster. Using a two-tier HIDE, distributed authentications are done within each disrupted network segment without changing any user interface. To share the encrypted data among the users of this application at (8) of II-C, other types of encryption schemes are required. Attribute Base Encryption is one of these candidates and can be used as a smooth extension of the procedure described in this poster[7]. An actual implementation must be produced using an appropriate toolkit such as CCNx to evaluate the performance. This will be performed in future research. The work for this paper was performed in the context of the FP7/NICT EU-JAPAN GreenICN project.

Large scale content distribution schemes that use named data networking (NDN) experience a copyright protection problem because of the nature of P2P-based, consumer-generated media (CGM) distribution. It is difficult to manage copyright violations by content uploaded in the network. To overcome this problem, NDN provides a content firewall that permits and rejects packets depending on its routing policy. In untrusted networks, however, the content firewall of each NDN router may not be updated as expected. In this paper, we present a PKI-based two-way content management scheme where a content owner or a system supervisor can delete illegal content from the network. First, a content owner sends a target content deletion request to a supervisor. After the supervisor's acknowledgment, the deletion request is distributed throughout the whole network. An extension of this content management system based on a secret sharing scheme was investigated to determine its security loopholes and scalability.

Wireless LAN multicast can provide high quality location-aware content service. However, our research revealed that multicast might cause a significant increase in the power consumption. Flexible Multicast Service (FMS) which is defined in the IEEE 802.11v enables power efficient multicast service. In this paper, we prove that the FMS strategy is not optimal and a little extension on FMS will achieve great improvement in power efficiency without throughput or delay penalties.

During a disaster, it is important to exchange information such as the magnitude of the disaster and safety confirmation. However, the communication infrastructure, such as a mobile phone network, may not be available after a large-scale disaster because current communication infrastructures have centralized control structures. Thus, it is important to design a network that can maintain a normal service using the remaining network resources, such as base stations and user terminals, even if the central servers are no longer available because of disconnections among servers. In this study, we developed a distributed SNS service, or autonomous distributed network, based on named data networking (NDN) with two-tier hierarchical ID-based encryption (HIDE) for authentication. We conducted a simulation of a residential area in the suburbs of Tokyo to demonstrate the performance of this SNS application, where it was used to disseminate safety confirmation. We present the average message delivery time with different decision intervals, the synchronization intervals, and the ratios of moving people.

We propose a single framework for cooperative spectrum sensing of cognitive radio network as well as for the self-organization of femtocells. This constructs a large-scale spectrum database through cooperative spectrum sensing for cognitive radio network, which exploits the existing infrastructure of the two-tier (macrocell-femtocell) network and encourages a small cellular network, i.e., femtocell, to act as the rendezvous point between individual local spectrum monitors and the fusion center of spectrum database. Distributed sensing results reported from many cognitive radio users can be integrated into spectrum database via these rendezvous points. Thus the problem of the dependency of conventional cooperative spectrum sensing on common control channel is improved. Meanwhile, the interaction between cognitive radio users and femtocells can offer an intriguing possibility to improve the self-organization of femtocells by absorbing radio environment maps constructed by cognitive radio users. Game theory can be applied to formulate the mutual benefits in the cooperation between cognitive radio user and femtocell. We illustrate the numerical effects of the coalitions between cognitive radio users and femtocells.

In emergent situations such as an earthquake, huge traffic from multiple services pours into IP Multimedia Subsystem (IMS) network and leads to a severe congestion problem. To protect IMS network, telecom companies usually take a measure of originator regulation on voice calls. However existing solutions are unable to maximize the service throughput for handling multiple services. This paper proposes an automatic originator regulation of IMS multiple traffic by stateless signal prioritization based on the types, message order and retransmissions of SIP messages within each call session. The best prioritization is to give a higher priority to a message type appearing at a later stage in each session and a lower priority to a retransmitted message. We also show the optimum queue length. For the effective confirmation of the safety at a disaster, an ideal communication system should pass more light-weight messages like instant messaging (IM) than those generated by voice calls. The simulation result shows the maximum throughput for each multimedia service is kept as in this ideal model even in an extremely congested situation with the 60 times larger offered load than usual which was observed in the 2011 earthquake off the Pacific coast of Tohoku.

Almost all recent mobile phones are equipped with multiple sensors, such as cameras, GPS, and accelerometers. By exploiting the sensing features, we capture many different events and share them over the mobile network. One of the most important challenges for such a participatory sensing system is the reduction of the battery consumption of the mobile device because the sensing task usually runs as a secondary task and should not disrupt the primary tasks of the mobile phone, such as phone calls. We overcome this problem by compressing the sensed data and sending a minimum amount of data over the wireless link. The compressed sensing (CS) technique is used for this compression with simple matrix operations at the mobile side, and the CPU-intensive reconstruction is performed on the resource-rich machine on the network side. In this paper, we validate this idea by implementing it on the iPhone/iPod platform. Since CS is a lossy compression technique, the reconstructed signal contains errors depending on the degree of sparseness of the original signal. We show that our system can reduce power consumption by approximately 16% compared with ZIP compression, and evaluate the reconstruction error using real sensing data of 86 test subjects.

Accelerometer data on a user's mobile phone contains abundant information that can be employed for user activity recognition. However, the existing schemes cannot provide accurate inference results under moving environments (e.g. on a train). This is because raw sensor data changes with the motion of the environment as well as the user. In this paper, we propose an enhanced collaborative recognition scheme that exploits neighborhood sensor data shared over a wireless network. Our preliminary experiment showed that the acceleration data of two different subjects on the same train was highly correlated. Further, it was possible to detect whether two subjects were on the same train with an accuracy of 69%. This result indicates that raw sensor data shared by spatially neighboring users can be used to detect transportation modes and enrich social networking applications.

Energy harvesting technology is one of the key technologies for the long-term operation of wireless sensor networks. However, power supply from such energy harvesting sources is not as stable as batteries. In order to compensate for the spatial and temporal variations of the energy harvesting sources, an energy storage device is used. Rechargeable batteries are commonly used in wireless sensor nodes. However, batteries can be charged and discharged for only a limited number of cycles. When the harvested energy is small, capacitors are better suited for energy storage because they can be charged and discharged quickly and efficiently. Moreover, the charge-discharge capability of capacitors does not degrade. The only critical problem of capacitors is that their energy leakage is too large to ignore. In this paper, we propose a capacitor leakage aware duty cycle control for energy harvesting wireless sensor networks. Our proposed method focuses on capacitor leakage reduction, which must be considered in a capacitor driven system but has not been considered to date. Our method maximizes the energy usage without degrading system availability by applying optimal control using multiple evaluations of the energy neutral operation and capacitor leakage.

This paper presents a simple but resilient method to suppress copyright violations among the content uploaded onto peer-to-peer (P2P) video sharing services, and is especially designed for consumer generated media (CGM). Encryption is a good way to block the circulation of illegal content. However, if the encryption key is caught by a malicious node in the P2P network, the ''denial of deletion'' ability offered by this key may make it difficult to stop the circulation of the content. To solve this problem, we propose a method to divide the encryption key into partial keys using the secret sharing scheme, and allowing them to be distributed into different nodes. Different from existing commercial P2P content distribution systems, this system is more scalable because the keys are managed in a distributed fashion. Regardless of the size of the P2P network, the probability of the encryption key being illegally used after the deletion operation for the target content is less than 0.1 even when more than 10% of the nodes are malicious.

This paper proposes a communication system using Wi-Fi (IEEE802.11g) to link between the Internet and high speed rail systems traveling at around 300km/h. In order to adapt Wi-Fi for high speed mobile communication, we optimized its coverage on a rail track with a developed directional antenna, which has a communication range of around 500m by 10mW. With the antenna, however, a mobile entity had to switch over antennae (a layer 2 handover (L2HO)) every 6 to 7 seconds. Furthermore Mobile IP handovers (a layer 3 handover (L3HO)) had to be appropriately controlled to avoid a simultaneous handover of Layer 2 and 3, which results in a fatal communication disruption. Therefore the designed system in this paper separated a L3HO from a L2HO. As a result, a maximum of 25Mbps with an average of 16Mbps for the UDP throughput and an average L2HO time of 110ms were realized while travelling at 270km/h.

The home networking becomes more interesting if users can share high quality contents with friends and colleagues living away from the user. DLNA certified devices allow users to share or access digital media contents on the same home network. However, the sharing of the content is only limited inside local area networks. In this paper, we propose a global content sharing home gateway named DAS (DLNA Agent for SNS). Different from exiting approaches using VPN, DAS enables to share specified contents to selected users with support of access control functionality provided by Social Network web services. As DAS behaves as a DLNA certified server, there is no need to modify commercial DLNA CE devices.

This paper shows a methodology of estimating a user's everyday energy expenditure using a 3-axis accelerometer of a mobile phone handset. We first infer the user's posture based on the acceleration sensor reading and calculate METS value, which is considered as a measure for estimating calorie consumption for daily activities. The experimental result shows that our application is as accurate as a reference device.

Recently, many kinds of real-time applications have become available over IP networks. It is important to measure network performance for such applications before making use of real applications. The authors developed a general purpose traffic measurement tool for IP networks. This system can generate any kind of traffic flexibly and calculate network performance such as throughput, delay and loss rate according to the packers to be observed. In this paper, the concept and implementation of this tool are described in detail. As an example of network measurements, we also conducted subjective assessment tests for Internet telephony and demonstrated the validity of this tool.

This paper introduces the outline of our speech understanding system. The overall flow of control is based on the bottom-up processing. The simulation system is under construction and consists of the hierarchically connected acoustic and lexical analyzers. The word recognition based on the phoneme recognition is performed as the main process of the acoustic analyzer. A continuous DP matching technique is applied for the connected digit recognition, after the lexical analyzer appoints the section that may contain a sequence of digits. The lexical analyzer consists of a parser and a discourse manager. The parser scans the input words in a left-to-right fashion, getting the grammatical and semantic rules of each key word from the dictionary entry. Then the connectivity of these key words are checked using the extracted rules. A verification on the existence of a digit sequence or a functional word between two milestone words is done at this stage. The output of a parser are filtered out by the discourse manager to choose a possible sentence under each context. The current task domain is the reception of international telephone call.