A method is described that can allocate bandwidth to each user flow fairly in a scalable network architecture such as differentiated services architecture. As promising queueing techniques for providing differentiated services, class-based packet scheduling and selective packet discarding have been attracting attention. However, if we consider that bandwidth should be allocated to each flow in a weighted manner, the parameters used in these methods such as the weight assigned to each class queue should be pre-determined appropriately based on an assumption about the number of flows in each class. Thus, when the actual traffic pattern differs from the assumed one, they may not work well. Instead of assuming the traffic conditions, our method estimates the number of active flows in each class by simple traffic measurement and dynamically changes the weight assigned to each class queue based on the estimated number. Our method does not need to maintain the per-flow state, which gives it scalability. Simulation showed that this method is effective under various patterns of the number of active flows.

Today, people want highly-customized products to satisfy their individual requirements. However traditional manufacturing technology is not geared towards high-mix, low-volume manufacturing. Holonic Manufacturing Systems (HMS) is a new paradigm to bridge this divide. HMS offers enterprises a new breed of technology to continuously reconfigure themselves to manufacture a larger variety of products in smaller batch sizes, and do this profitably. A suitable metaphor for implementing the holonic manufacturing system is the emerging IEC function block architecture. The paper describes how function blocks can be used to build such holonic manufacturing systems. We also illustrate the merits of our approach through a real-world engine assembly line being developed by DaimlerChrysler.

In this paper, we propose a new type of hybrid ARQ protocol, in which a channel-adaptive variable rate channel coding scheme is combined with a multi-copy retransmission strategy so as to enhance the system performance under the delay constraint of real-time ATM services in broadband radio access networks. The main feature of a multi-copy retransmission strategy in this scheme is to improve the average throughput for a given Forward Error Correction (FEC) rate, subject to the prescribed cell loss requirement of the real-time wireless ATM services, while augmenting the reliability of channel state information required for a channel-adaptive FEC scheme. Our analysis shows that under a harsh fading channel, the proposed approach is useful for achieving the prescribed cell loss performance without significantly degrading the average throughput performance.

Successful e-commerce presupposes techniques by which autonomous trading entities can interoperate. Although progress has been made on data exchange and payment protocols, interoperation in the face of autonomy is still inadequately understood. Current techniques, designed for closed environments, support only the simplest interactions. We develop a multiagent approach for interoperation of business process in e-commerce. This approach consists of (1) a behavioral model to specify autonomous, heterogeneous agents representing different trading entities (businesses, consumers, brokers), (2) a metamodel that provides a language (based on XML) for specifying a variety of service agreements and accommodating exceptions and revisions, and (3) an execution architecture that supports persistent and dynamic (re)execution.

This paper describes an electromagnetically coupled microstrip divider that provides high output port isolation and DC cutting. The device consists of a parasitic resonator placed above microstrip patch resonators, achieving tight coupling for both input and output ports. FDTD simulation and measurements reveal that the device has a high isolation between output ports. Equal and unequal 2-way and 3-way power dividers are presented in this paper.

A class E low dv/dt PWM synchronous rectifier regulating the output voltage at a fixed frequency is presented, analyzed and verified experimentally. This rectifier is derived from the class E low dv/dt rectifier by replacing the controlled switch (MOSFET with its anti-parallel diode) with the rectifier diode in class E low dv/dt rectifier, and by using the synchronized PWM signal to control the output voltage at desired value. The ZVS condition of the controlled switch can be maintained from full-loaded to open-loaded. The experimental results measured at switching frequency 1 MHz are in good agreement with the theoretical prediction.

This paper introduces current-mode biquad using multiple current output operational transconductance amplifiers (OTAs) and grounded capacitors. The circuit configuration is obtained from a second-order integrator loop structure with loss-less and lossy integrators. The proposed circuit can realize low-pass, band-pass, high-pass, band-stop and all-pass transfer functions by suitably choosing the input and output terminals. And the circuit characteristics can be electronically tuned through adjusting the transconductance gains of OTAs. It is also made clear that the proposed circuit has very low sensitivities with respect to the circuit active and passive elements. An example is given together with simulated results by PSpice.

Tree-based approach has been proven to be most scalable for one-to-many reliable multicast. It efficiently combines distributed recovery with local recovery over a logical tree of the sender and receivers. It has also been known that the performance of the tree-based protocols heavily depends upon the quality of the logical tree. In this paper, we propose an end-to-end scheme to further enhance the scalability of the tree-based approach. By exchanging packet loss information observed at the end hosts, the scheme constructs and maintains a logical tree congruent with the underlying multicast routing tree even in the presence of session membership and multicast route changes. The scheme also groups the tree nodes and assigns separate multicast addresses to them in order to enable efficient multicast retransmission for reducing both delay and exposure. We compare the proposed scheme with Tree-based Multicast Transport Protocol (TMTP), a static tree-based protocol. Extensive simulations up to 300 node sessions reveal that the proposed scheme reduces implosion and exposure more than 20% and 50%, respectively. The results also indicate that the scheme is highly scalable such that the improvement gets more significant as the size of the session increases.

Focusing on a distributed control service-control-node (SCP) that houses a database (DB) distributed across multiple modules, this paper proposes an autonomous distributed SCP architecture using multicasting access to the distributed DB, and highlights its application areas. We assume as a basic condition that neither the network nor the other modules in the system are aware of the DB configuration. Based on this condition, we propose two basic methods: a unicast approach in which the DB management module that is selected at random by the network routes the DB access request to the module where the target data resides (Method A), and a multicast method in which DB access requests are broadcast to all modules (Method B). A quantitative evaluation is made of the number of required modules and required communications performance between modules which is determined by the capacity of the main memory and processing capacity of the processors. Based on the results, we conclude that Method B better exploits the advantages of module autonomous distribution technology within the limits that the economy of inter-module communication overhead is not impaired. Furthermore, in the event a module fails in Method B, a scheme is proposed in which the defective module is cut out of the multicast group, and multicasting continues. This could be implemented most effectively using a separate route under hardware control that is independent of the on-line communications route between modules.

Wireless mobile communication networks support mobile terminals (MTs) which are free to travel within a service coverage area. In order to locate an MT effectively when a call is initiated, several location management schemes are proposed to keep track of its location. Current methods being used in IS-41 and GSM MAP for location management pose problems such as an increase in signaling traffic in the network, a ping-pong effect and a bottleneck created by signaling traffic at home location register (HLR). In this paper, we propose a new location management scheme that is to reduce the number of location registrations at HLR by making the location registration at HLR unnecessary when an MT moves into neighboring registration area (RA) or when it moves back to the original RA from neighboring RA. Our scheme employs a centralized database architecture using the HLR/VLR concept as in the IS-41 and GSM MAP but alleviates the above-mentioned problems. Analysis results show that our scheme always outperforms current methods and shows an especially better performance at low CMR (call to mobility ratio).

The imprecise computation is one of the promising schemes in the real time systems to adapt quality of computations to change of load with keeping the deadlines of tasks in the systems. When overload occurs in the systems, the minimum requirements on the deadline are assured by decreasing quality of the computation. This paper describes how to apply the concept of the imprecise computation to automobile control in the expressway assuming the intelligent transportation system (shortly, ITS). The deadline violation of tasks for automobile control in the expressway induces collision of automobiles. Regardless of whether the expressway is congested or not, collision of automobiles must be avoided. To satisfy such requirement, the concept of the imprecise computation is effective. This paper proposes an adaptive scheduling using the imprecise computation to avoid collision of automobiles and increase throughput, and shows results of simulation experiments about an adaptive scheduling for automobiles control.

The IETF Differentiated Services (DiffServ) framework achieves scalability by (1) aggregating traffic flows with coarse grain QoS on the data plane, and (2) allocating network resources with a bandwidth broker (BB) on the control plane. However, there are many issues that need to be addressed under such framework. First, it has been shown that the concatenation of strict priority (SP) scheduler of class-based queues (CBQ) can cause delay jitter unbounded under certain utilization, which is not acceptable to support the premium service (PS). Furthermore, it is not clear how such a DiffServ network can support traffic flows requiring the guaranteed service (GS), which is a desirable feature of the future Internet. This paper presents architecture and mechanisms to support multiple QoS under the DiffServ paradigm. On the data plane, we present a node architecture based on the virtual time reference system (VTRS). The key building block of our node architecture is the core-stateless virtual clock (CSVC) scheduling algorithm, which, in terms of providing delay guarantee, has the same expressive power as a stateful weighted fair queueing (WFQ) scheduler. With the CSVC scheduler as our building block, we design a node architecture that is capable of supporting integrated transport of the GS, the PS, the assured service (AS), and the traditional best effort (BE) service. On the control plane, we present a BB architecture to provide flexible resource allocation and QoS provisioning. Simulation results demonstrate that our architecture and mechanisms can provide scalable and flexible transport of integrated traffic of the GS, the PS, the AS, and the BE services.

Before we gave a fast generalized minimum distance (GMD) decoding algorithm for one-point algebraic-geometry (AG) codes. In this paper, we propose another fast GMD decoding algorithm for these codes, where the present method includes an erasure deletion procedure while the past one uses an erasure addition procedure. Both methods find a minimal polynomial set of a given syndrome array, which is a candidate for an erasure-and-error locator polynomial set constrained with an erasure locator set of each size. Although both erasure addition and deletion GMD decoding algorithms have been established for one-dimensional algebraic codes such as RS codes, nothing but the erasure addition GMD decoding algorithm for multidimensional algebraic codes such as one-point AG codes have been given. The present erasure deletion GMD decoding algorithm is based on the Berlekamp-Massey-Sakata (BMS) algorithm from the standpoint of constrained multidimensional shift register synthesis. It is expected that both our past and present methods play a joint role in decoding for one-point AG codes up to the error correction bound.

A new algorithm for the maximum a posteriori (MAP) decoding of linear block codes is presented. The proposed algorithm can be regarded as a conventional BCJR algorithm for a section trellis diagram, where branch metrics of the trellis are computed by the recursive MAP algorithm proposed by the authors. The decoding complexity of the proposed algorithm depends on the sectionalization of the trellis. A systematic way to find the optimum sectionalization which minimizes the complexity is also presented. Since the algorithm can be regarded as a generalization of both of the BCJR and the recursive MAP algorithms, the complexity of the proposed algorithm cannot be larger than those algorithms, as far as the sectionalization is chosen appropriately.

Power supply rejection ratio (PSRR) characteristics of a switched capacitor filter (SCF) is improved when using an equal level diagram design of a leapfrog type filter. By using this design method, it is shown that PSRR of a SCF measured is improved about 20 dB.

Due to the advancements in Information Technology, such as the Internet and the presence of fierce competition in the market, the business environment is changing rapidly. To cope with these dynamic changes, heterogeneous systems are now required to integrate in order to form alliances with different business units or within individual business units. Since business operations can not be stopped to carry out these changes in the existing systems, the systems are required to integrate flexibly, preserving each constituent's individual characteristics. By implementing Atomic Action through a gateway and across constituent systems in a Heterogeneous Autonomous Decentralized System (HADS), higher degrees of assurance can be achieved through cooperation. However, if all the transactions are passed through a gateway, the response time worsens and the result cannot be obtained within an appropriate timeframe. Hence, a new technique of suppressing the flow passing through the gateway, while achieving a maximum number of successful transaction within the appropriate timeframe, is required.

Multisignature scheme realizes that plural users generate the signature on a message, and that the signature is verified. Various studies on multisignature have been proposed. They are classified into two types: RSA-based multisignature, and discrete logarithm problem (DLP) based multisignature, all of which assume that a message is fixed beforehand. In a sense, these schemes do not have a feature of message flexibility. Furthermore all schemes which satisfy with order verifiability designate order of signers beforehand. Therefore these protocols have a feature of order verifiability but not order flexibility. For a practical purpose of circulating messages soundly through Internet, a multisignature scheme with message flexibility, order flexibility and order verifiability should be required. However, unfortunately, all previous multisignature do not realize these features. In this paper, we propose a general model of multisignature schemes with flexibility and verifiability. We also present two practical schemes based on DLP based message recover signature and RSA signature, respectively.

This study investigates the problem of unfairness when QoS routing does not consider the mix of traffic classes. Unfairness is mainly caused by routing different traffic flows of the same class through paths with extremely different traffic mixtures, involving various service classes. Next, a new routing scheme--Service-sensitive Routing (SSR), which takes the state of traffic mixture of the various service classes into account, is proposed. To determine the QoS route for a flow request, SSR not only considers the available bandwidth and delay of the candidate paths, but also considers the mix of traffic classes on the paths. Additionally, the hybrid granularity routing decision in SSR scheme is scalable and suitable for the Differentiated Services and MPLS networks. Extensive simulations show that SSR can effectively reduce the variance of the average of queuing delays, for example by approximately 20% to 35% for a moderate offered load, compared to the shortest path routing. Furthermore, this routing scheme reduces the fractional reward loss and bandwidth blocking probability.

Generally, the wavelet transform is applied for watermarking, where a whole image is transformed to the frequency domain. However, many schemes which adopt the wavelet transform are weak for StirMark attack designed to affect locally such as rotation, extension, reduction, etc. In this paper, we propose a new scheme which applies the wavelet transform locally and has a tolerance for StirMark attack. How to maintain the quality of the watermarked image is also shown.

This paper describes the implementation of a proposed image filter into a Discrete-Time Cellular Neural Network (DT-CNN). The three stages that compose the filter are described, showing that the resultant filter is capable of (1) erasing or detecting several concentric shapes simultaneously, (2) thresholding and (3) thinning of gray-scale images. Because the DT-CNN has to fill certain conditions for this filter to be implemented, it becomes a modified version of a DT-CNN. Those conditions are described and also experimental results are clearly shown.