We present a novel RFID middleware architecture, Otedama, which makes use of a unique property of RFID information to improve performance. RFID tags are bound to items. New information related to an RFID tag is generated at the site where the ID exists, and the entity most interested in the history and the item itself is in close proximity to the RFID tag. To exploit this property, we propose a scheme which bundles information related to a specific ID into one object and moves that bundle to a nearby server as the RFID tag moves from place to place. By using this scheme, information is always accessible by querying a system near the physical location of the tag, providing better query performance. Additionally, the volume of records that must be kept by a repository manager is reduced, because the relocation naturally migrates data away as physical objects move. We show the effectiveness of this architecture by analyzing data from a major retailer, finding that information retrieval performance will be six times better, and the cost of search is possibly several times cheaper.

QoS of applications is essential for content providers, and it is required to improve the end-to-end communication quality from a content provider to users. Generally, a content provider's data center network is connected to multiple ASes and has multiple egress paths to reach the content user's network. However, on the Internet, the communication quality of network paths outside of the provider's administrative domain is a black box, so multiple egress paths cannot be quantitatively compared. In addition, it is impossible to determine a unique egress path within a network domain because the parameters that affect the QoS of the content are different for each network. We propose a “Performance Aware Egress Path Discovery” method to improve QoS for content providers. The proposed method uses two techniques: Egress Peer Engineering with Segment Routing over IPv6 and Passive End-to-End Measurement. The method is superior in that it allows various metrics depending on the type of content and can be used for measurements without affecting existing systems. To evaluate our method, we deployed the Performance Aware Egress Path Discovery System in an existing content provider network and conducted experiments to provide production services. Our findings from the experiment show that, in this network, 15.9% of users can expect a 30Mbps throughput improvement, and 13.7% of users can expect a 10ms RTT improvement.

An efficient algorithm is proposed for finding all dc solutions of piecewise-linear (PWL) circuits. This algorithm is based on a powerful test (termed the LP test) for nonexistence of a solution to a system of PWL equations in a given region using the dual simplex method. The proposed algorithm also uses a special technique that decreases the number of regions on which the LP test is performed. By numerical examples, it is shown that the proposed algorithm could find all solutions of large scale problems, including those where the number of variables is 500 and the number of linear regions is 10500, in practical computation time.

An experimental remote jazz jam session with uncompressed HDTV over the Internet was conducted on September 21st as a Grand Final event of the Aichi Exposition 2005. Professional jazz musicians located at the venue of Aichi Exposition and at SARA in Amsterdam have made the jazz jam session with new mechanisms called as "Internet Metronome" and "delay-control unit" using an international "lightpath." This was the first music collaboration using a new methodology and, one of the challenging demonstrations to transport the uncompressed HDTV streams with timing control under the current software and hardware architectures. "Internet Metronome" and "delay-control unit" enabled to make a tempo using and controlling delay, and "lightpath" minimized the network jitter. Using these new mechanisms and technology, the musicians could play with new music collaboration environment over the Internet with long communication delay, and enjoyed remote jazz jam session at both ends.

Improvements of Internet technology during the last decade have shifted the technical focus from reachability to the quality of communication. There are many technical frameworks, such as Integrated Service and Differentiated Services, which have been standardized to assure the quality of communication. QoS routing is also one of such frameworks. It changes or fixes a route that IP datagrams take, and is also indispensable to put a variety of services into practice. Nevertheless, experiment reports of QoS routing on operational network are quite few, especially with dynamic SLA. Therefore, we still do not know much about the important factors for QoS-enabled network to be realized, such as users' behavior, suitable services to offer, and configuration parameters. In this paper, we carried out field-trial with pseudo QoS routing and dynamic SLA in an actual network built at the WIDE retreat in autumn 2000. In this field-trial, we provided two different types of links to attendees. Attendees chose one of the links, through which their flows go, with our dynamic SLA. We describe the details and the results of this experiment. Our results could help to understand the customers' behavior for differentiated services, and therefore be useful for designing and deploying various QoS technologies.

In this paper, we implemented practical resource adaptation mechanism for broadband application environment especially suitable for portable computers (note PCs) with limited power supply. Continuous development of portability enhancement and increasing computation with less power consumption for battery operating environment in note PC equips with intelligent resource controlling mechanism embedded inside the hardware. In such environment, where occasional environmental changes take in place rapidly, adaptive and collaborative controls of resources are required. Optimization of resource based on power supply management is dedicated to the operating environment. Bi-directional, user, application, operating system and device aware interface for resource configuration/management is extended to the current Unix operating system by implementing application programming interface of Advanced Configuration and Power Interface (ACPI). Traditional operating system conceals the active device probing and controlling method autonomously. Implementation of "State handler daemon" interface enables applications and application users to monitor and adapt the resources available during the operation. Thick collaboration between application and devices that are reserved in its limited environments economizes the consuming device utilization resulting: for example, life extension of battery life and effective network bandwidth adaptation. We focused on DVTS (Digital Video Transport System) as a typical broadband application. Evaluation shows 125 minutes of continuous battery operation with battery life extension compared to 70 minutes with traditional systems. Collaboration with network device management enables 100% packet transfer compared to 89% without any Resource adaptations.

An efficient algorithm is proposed for finding all solutions of piecewise-linear resistive circuits containing bipolar transistors. This algorithm is based on a powerful test (termed the LP test) for nonexistence of a solution in a given region using linear programming (LP). In the LP test, an LP problem is formulated by surrounding the exponential functions in the Ebers-Moll model by right-angled triangles, and it is solved by LP, for example, by the simplex method. In this paper, it is shown that the LP test can be performed by the dual simplex method, which makes the number of pivotings much smaller. Effectiveness of the proposed technique is confirmed by numerical examples.

This paper proposes a spectrum-overlapped resource management (SORM) technique where each user equipment (UE) can ideally obtain the frequency selection diversity gain under multi-user environments. In the SORM technique for cellular systems, under assumption of adopting a soft canceller with minimum mean square error (SC/MMSE) turbo equalizer, an evolved node B (eNB) accepts overlapped frequency resource allocation. As a result, each UE can use the frequency bins having the highest channel gain. However, the SORM becomes non-orthogonal access when the frequency bins having high channel gain for UEs are partially identical. In this case, the inter-user interference (IUI) caused by overlapping spectra among UEs is eventually canceled out by using the SC/MMSE turbo equalizer. Therefore, SORM can achieve better performance than orthogonal access e.g. FDMA when the IUI is completely canceled. This paper demonstrates that SORM has the potential to improve transmission performance, by extrinsic information transfer (EXIT) analysis. Moreover, this paper evaluates the block error rate (BLER) performance of the SORM and the FDMA. Consequently, this paper shows that the SORM outperforms the FDMA.

UHF radio frequency identification (RFID) has gathered significant interest in the field of long-distance automatic identification applications. Since UHF RFID shares the frequency band with other RFID and/or other wireless systems, it is important to determine how much interference can be applied without causing a significant degradation of anti-collision speed. In this paper, the permissible link quality for RFID anti-collision in a practical environment is discussed by considering an erroneous communication link, taking into account of bit encoding and the type of interference. We approach the quantification of permissible link quality experimentally along with protocol simulations and the mathematical analyses. An international standard protocol, employing frame slotted ALOHA, was used as the air protocol. For these investigations, the present authors developed a protocol simulator. The simulation results were compared with analytical values based on Poisson distribution. The investigation in the return (tag to reader) link, and the forward (reader to tag) link, were analyzed separately. As result of the protocol simulation, it is generally important to secure the Pulse Error Rate 10-4 or better in both return and forward links for the anti-collision of 64 or less tags. The quality of the return link may be relaxed when the application does not require fast anti-collision. The degradation of the forward link, on the other hand, may entail loss of important commands, resulting in extremely slow anti-collision. It is measured experimentally that the required link quality can be relaxed by up to 10 dB in the return links and by 5 dB in the forward link when the primary source of interference originates in the interfering readers.

Failure avoidance capability is a desired feature for telecommunication networks, such as the Internet. However, not all failures can be promptly bypassed on the Internet because routing systems that are responsible for detecting and avoiding failures cannot detect all failures. Consequently, failures can interrupt internet communications for a long time, such as a few hours. This paper proposes a novel routing architecture called Drouting that enables flexible failure avoidance. In Drouting, routers calculate multipaths from a source to a destination by constructing Directed Acyclic Graphs (DAGs) that include all links in the intra-domain network graph. IP packets carry packet tags that are set by the end host. The packet tags are used to select a network path from the multipath routes. In this paper, the failure avoidance property of Drouting architecture is evaluated through comparison with another proposal, Deflection, using simulations. Simulations were performed on inferred and synthetic topologies. Drouting exhibits similar performance with Deflection in terms of the number of nexthops, the number of paths and the length of paths, while Drouting outperforms Deflection in the probability of success of failure avoidance.

Congestion Control Scheme of TCP/IP protocol suite is established by Transmission Control Protocol (TCP). Using the self-clocking scheme, TCP is able to maintain a quick optimum connection status for the network path, unless it is given an excessive load to carry to the network. However, in wide area networks, there are some obstructive factors for the self-clocking scheme of TCP. In this paper, we describe the obstructive factors for the self-clocking scheme. We propose a new congestion control scheme using a packet pair scheme and a traffic-shaping scheme. In combining these schemes with TCP, new TCP options and a modification for TCP congestion control algorithms are added. Using our scheme, TCP is able to maintain smooth self-clocking. We implemented this scheme on a network simulator for evaluation. Compared with normal TCP, this scheme was demonstrated to be over 20% more efficient in symmetric communication and over 40% more efficient in asymmetric communication.

MC-CDMA is an attractive multi-access method for the next generation high-speed mobile communication systems. The uplink transmission performance is limited by the multi-access interference (MAI) from other users since all users share the same bandwidth. Adaptive antenna array can be used to suppress the MAI and to improve the uplink transmission performance. In this paper, we propose a frequency-domain adaptive antenna array for multi-code MC-CDMA. The proposed frequency-domain adaptive antenna array uses a simple normalized LMS (NLMS) algorithm. Although the NLMS algorithm is used, very fast weight convergence within one MC-CDMA symbol duration is achieved since the weight updating is possible as many times as the number of subcarriers within one MC-CDMA symbol duration.