A triple density Error Diffusion for medical monochrome LCDs is proposed to improve their gray-scale precisions. In addition, a measurement technique of image qualities based on E-MSE (Eye model-based Mean Square Error) is proposed. Several conventional techniques for medical LCDs, such as Sub-Pixel Modulation and Error Diffusion, are evaluated based on E-MSE and the validity of the proposed technique is ensured objectively.

This paper deals with the diffraction of TM plane wave by a perfectly conductive periodic surface. Applying the Rayleigh hypothesis, a linear equation system determining the diffraction amplitudes is derived. The linear equation is formally solved by Cramer's formula. It is then found that, when the angle of incidence becomes a low grazing limit, the amplitude of the specular reflection becomes -1 and any other diffraction amplitudes vanish for any perfectly conductive periodic surfaces with small roughness and gentle slope.

A probe-fed U-shaped cross-sectional antenna with tuning stubs on a U-shaped ground plane is proposed for wideband applications. The bottom of the antenna is etched to form tuning stubs for impedance matching. The simulated results of return loss, co- and cross-polarized patterns are presented and compared with the measured ones. Characteristics of a constructed antenna prototype at the operating frequency show that the antenna has an impedance bandwidth (2:1 VSWR) of 37.44% and average gain level of 8.5 dBi. Good radiation characteristics of the proposed antenna have been obtained that is the cross-polarization level and front-to-back ratio in both E- and H-planes across the large bandwidth are better than 22 dB and 12 dB, respectively.

Supporting Quality of Service (QoS) over the Internet is a very important issue and many mechanism have been already devised or are under way towards achieving this goal. One of the most important approaches is the class-based architecture, which provides a scalable mechanism for QoS support in a TCP/IP network. Class-based service differentiation can be realized without resource reservation, admission control and traffic policing. However, the resulting services are only relative. While it is, in principle, not feasible to provision for absolute guarantees without admission control and/or traffic policing, such a service can be reasonably well emulated using adaptive rate allocation at the link scheduler of routers. In this paper, we propose mechanism for link scheduler of router that achieve emulated absolute and other relative guarantees using dynamic weighted fair queueing (DWFQ) combining with class packet dropping. The weights of DWFQ are frequently adjusted to current load conditions and based on prediction of realistic class traffic. These mechanisms can realize many approaches to QoS guarantees and class-based differentiation.

Network congestion and random errors of wireless link are two well-known noteworthy parameters which degrade the TCP performance over heterogeneous networks. We put forward a novel end-to-end TCP congestion control mechanism, namely TCP BaLDE (Bandwidth and Loss Differentiation Estimate), in which the TCP congestion control categorizes the reason of the packet loss by estimating loss differentiation in order to control the packet transmission rate appropriately. While controlling transmission rate depends on the available bandwidth estimation which is apprehended by the bandwidth estimation algorithm when the sender receives a new ACK with incipient congestion signal, duplicates ACKs or is triggered by retransmission timeout event. Especially, this helps the sender to avoid router queue overflow by opportunely entering the congestion avoidance phase. In simulation, we experimented under numerous different network conditions. The results show that TCP BaLDE can achieve robustness in aspect of stability, accuracy and rapidity of the estimate in comparison with TCP Westwood, and tolerate ACK compression. It can achieve better performance than TCP Reno and TCP Westwood. Moreover, it is fair on bottleneck sharing to multiple TCP flows of the same TCP version, and friendly to existing TCP version.

A differential detection Space-Time Block Code (STBC) is proposed with a high transmission rate, allowing a trade-off between diversity and multiplexing gain with low encoding and decoding complexity. The proposed method offers multiplexing gain by doubling the transmission rate for three and four transmission antennas. Computer simulations demonstrate that the proposed STBC can achieve a 5.8 dB Eb/N0 gain at BER = 10-3 compared with a conventional differential detection STBC for four transmission and two receiving antennas.

This paper presents a shortest path search algorithm using a model of excitable reaction-diffusion dynamics. In our previous work, we have proposed a framework of Digital Reaction-Diffusion System (DRDS)--a model of a discrete-time discrete-space reaction-diffusion system useful for nonlinear signal processing tasks. In this paper, we design a special DRDS, called an "excitable DRDS," which emulates excitable reaction-diffusion dynamics and produces traveling waves. We also demonstrate an application of the excitable DRDS to the shortest path search problem defined on two-dimensional (2-D) space with arbitrary boundary conditions.

This paper proposes a framework for session-level SLA (Service Level Agreement) and network-level SLA management to provide QoS-oriented application services over DiffServ/MPLS networks. DiffServ and MPLS technologies enhance the capability of QoS guarantee on IP network, and application service provider can provide QoS-oriented application services to their customers based on the transport networks. The example of using our approaches in the VoIP service involving the network service provider, the VoIP service provider, and the VoIP customers are examined. The session-level SLA between VoIP service provider and VoIP customer and the network-level SLA (N-SLA) between network provider and VoIP service provider are constructed in this paper. Besides, the VoIP service provider faces the QoS-mapping issue and the balance between revenue and cost, i.e., how to contract the N-SLA. Therefore, we introduce an off-line SLA evaluation scheme, a heuristic optimization algorithm and an on-line SLA process method to provide VoIP service policy, and then the optimal QoS-mapping can be resolved. The concept of this framework of session-level SLA and network-level SLA management can be extended easily into other real-time multimedia and non-real time data services.

Differentiated-services model has been prevailed as a scalable solution to provide quality of service over the Internet. Many researches have been focused on per hop behavior or a single domain behavior to enhance quality of service. Thus, there are still difficulties in providing the end-to-end guaranteed service when the path between sender and receiver includes multiple domains. Furthermore differentiated-services model mainly considers quality of service for traffic aggregates due to the scalability, and the quality of service state may be time varying according to the network conditions in the case of relative service model, which make the problem more challenging to guarantee the end-to-end quality-of-service. In this paper, we study class mapping mechanisms along the path to provide the end-to-end guaranteed quality of service with the minimum networking price over multiple differentiated-services domains. The proposed mechanism includes an effective implementation of relative differentiated-services model, quality of service advertising mechanism and class selecting mechanisms. Finally, the experimental results are provided to show the performance of the proposed algorithm.

This paper introduces a network-aware video delivery framework where the quality-of-service (QoS) interaction between prioritized packet video and relative differentiated service (DiffServ) network is taken into account. With this framework, we propose a dynamic class mapping (DCM) scheme to allow video applications to cope with service degradation and class-based resource constraint in a time-varying network environment. In the proposed scheme, an explicit congestion notification (ECN)-based feedback mechanism is utilized to notify the status of network classes and the received service quality assessment to the end-host applications urgently. Based on the feedback information, DCM agent at ingress point can dynamically re-map each packet onto a network class in order to satisfy the desired QoS requirement. Simulation results verify the enhanced QoS performance of the streaming video application by comparing the static class-mapping and the class re-mapping based on loss-driven feedback.

We propose the concept of an opinion model for interactive multimodal services and apply it to an audiovisual communication service. First, psychological factors of an audiovisual communication service were extracted by using the semantic differential (SD) technique and factor analysis. Forty subjects participated in subjective tests and performed point-to-point conversational tasks on a PC-based video phone that exhibited various network qualities. The subjects assessed those qualities on the basis of 25 pairs of adjectives. Two psychological factors, i.e., an aesthetic feeling and a feeling of activity, were extracted from the results. Then, quality impairment factors affecting these two psychological factors were analyzed. We found that the aesthetic feeling was affected by IP packet loss and video coding bit rate, and the feeling of activity depended on delay time, video packet loss, video coding bit rate, and video frame rate. Using this result, we formulated an opinion model derived from the relationships among quality impairment factors, psychological factors, and overall quality. The validation test results indicated that the estimation error of our model was almost equivalent to the statistical reliability of the subjective score.

Admission control is becoming an essential technique for IP networks to provide full-fledged multimedia streaming services. Although signaling-based schemes are utilized to achieve this, these are difficult to deploy and can hardly achieve strict admission control taking the properties of packet arrival into consideration. In this paper, we propose a novel admission control strategy called the Tentative Accommodating and Congestion Confirming Strategy (TACCS). The main idea is to accommodate incoming flows tentatively and confirm congestion after a certain period. Since tentative accommodating enables us to generate the same situation as where incoming flows have been accommodated, TACCS makes it possible to control admission considering the properties of packet arrival after they have been accommodated, without collecting resource information in advance. From the results of mathematical analysis, we confirmed that TACCS enabled a domain to control admission without a centralized management agent and we provided guidelines for configuring parameters of TACCS.

This paper proposes new candidate one-way functions constructed with a certain type of endomorphisms on non-supersingular elliptic curves. We can show that the one-wayness of our proposed functions is equivalent to some special cases of the co-Diffie-Hellman assumption. Also a digital signature scheme is explicitly described using our proposed functions.

This paper presents the design of low-power low-noise 10 GHz CMOS monolithic integrated LC VCOs suitable for data clock recovery architectures in optical receivers of SDH (STM-64) and SONET (OC-192). Optimizations of device parameters and passive components are given in detail. For passive components, differential and single-ended inductor structures as well as MOS varactors with and without lightly doped drain/source (LDD) implantation have been investigated. The VCOs implemented in a 0.18 µm process demonstrate the single-side-band phase noise of as low as -107 dBc/Hz at 1 MHz offset and 21% tuning range while consuming only 7 mW under 1.8 V supply.

In this paper, an efficient equivalence checking method for two C descriptions is described. The equivalence of two C descriptions is proved by symbolic simulation. Symbolic simulation used in this paper can prove the equivalence of all of the variables in the descriptions. However, it takes long time to verify the equivalence of all of the variables if large descriptions are given. Therefore, in order to improve the verification, our method identifies textual differences between descriptions. The identified textual differences are used to reduce the number of equivalence checkings among variables. The proposed method has been implemented in C language and evaluated with several C descriptions.

In [1], an algorithm based on phase variations of received pilot symbols was proposed to estimate one of the most important channel parameters, maximum Doppler shift, fd. However, AWGN (Additive white gauss noise) will cause large estimation error in some cases. In order to analyze the influence of noise, we extended the phase probability density function (pdf) in [1] to the scenario with both fading and AWGN, then the estimation error is characterized in closed-form expression. By this error expression, we found that power control will affect the estimator of [1] and we proposed a modification method based on SNR estimation to obtain accurate Doppler shift estimation in moderate low SNRs (signal-to-noise ratio). Simulation results show high accuracy in wide range of velocities and SNRs.

This paper proposes a logic synthesis technique for asymmetric slope differential dynamic logic (ASDDL) circuits. The technique utilizes a commercially available logic synthesis tool that has been well established for static CMOS logic design, where an intermediate library is devised for logic synthesis likely as static CMOS, and then a resulting synthesized circuit is translated automatically into ASDDL implementation at the gate-level logic schematic level as well as at the physical-layout level. A design example of an ASDDL 16-bit multiplier synthesized in a 0.18-µm CMOS technology shows an operation delay time of 1.82 nsec, which is a 32% improvement over a static CMOS design with a static logic standard-cell library that is finely tuned for energy-delay products. Design with the 16-bit multiplier led to a design time for an ASDDL based dynamic digital circuit 300 times shorter than that using a fully handcrafted design, and comparable with a static CMOS design.

Asymmetric slope differential CMOS (ASD-CMOS) and asymmetric slope differential dynamic logic (ASDDL) surpass the highest speed that conventional CMOS logic circuits can achieve, resulting from deeply shortened rise time along with relatively prolonged fall time. ASD-CMOS is a static logic and ASDDL is a dynamic logic without per-gate synchronous clock signal, each of which needs two-phase operation as well as differential signaling, however, interleaved precharging hides the prolonged fall time and BDD-based compound logic design mitigates area increase. ASD-CMOS 16-bit multiplier in a 0.18-µm CMOS technology demonstrates 1.78 nsec per an operation, which reaches 34% reduction of the best delay time achieved by a multiplier using a CMOS standard cell library that is conventional yet tuned to the optimum in energy-delay products. ASDDL can be superior to DCVS-DOMINO circuits not only in delay time but also in area and even in power. ASDDL 16-bit multiplier achieves delay and power reduction of 4% and 20%, respectively, compared with DCVS-DOMINO realization. A prototype ASD-CMOS 16-bit multiplier with built-in test circuitry fabricated in a 0.13-µm CMOS technology operates with the delay time of 1.57 nsec at 1.2 V.

In this paper, we address how to efficiently support differentiated services with the optimized bandwidth reservation in a polling-based generalized TDMA network like E-PON (Ethernet Passive Optical Network). In E-PON, performances of service differentiation for QoS (Quality of Service) guaranteed multiples services are directly affected by the bandwidth reservation algorithm of ONU (Optical Network Unit) in addition to the priority-based packet scheduling. Our proposed Service Quality Pre-engagement (SQP) algorithm reduces the system buffer size, the light-load penalty problem and the service interference among classes effectively by partially introducing the dynamic forward recurrence reservation scheme for QoS guaranteed classes. We also introduce the FRC(Forward Reservation Class) Selection algorithm that preserves the optimized reservation bandwidth to minimize the unnecessary reservation contentions. These algorithms do not mandate the basic concept of DBA and request the similar amount of REPORT bandwidth. The analytic and simulation results are performed to evaluate the performances of the proposed algorithms.

Millimeter-wave (MMW) communication systems, specially from 60 GHz band, are expected to play a key role in realizing the intelligent transportation system (ITS) for high date rate and mulitmedia communications. During the last years, System-in-package (SiP) solutions for MMW RF-transceiver have become an attractive alternative to System-on-Chip (SoC) approaches. In the scheme, active circuits are integrated with passive circuit much tightly. Traditional distributed hybrid circuit concept, such as ADS and Microwave Office, is not quite applicable for SiP, specially in MMW frequency. In this paper, an improved finite-difference time-domain formulation using the matrix theory and an improved integral transform is presented to solve hybrid high-order linear lumped circuit and passive circuit problem implicitly instead of explicit method used for traditional FDTD method. In this improved method, general high-order linear lumped circuit is expressed firstly as not only one equation but also equations set according kirchhoff's laws. Then, a local iterative matrix expression connecting with each active circuit can be built when EM fields, current/current density and interior variable of equations set are treated as separated vector element. In order to make this formulation stable, an improved integral transform is proposed to reform the matrix's condition number. Simulations show that the results by our improved FDTD formulation can effectively not only keep the accuracy of passive circuit, but also integrate high-order linear lumped circuit expressed by equations set as well as one equation.