A novel first order voltage-mode non-inverting and inverting output of all-pass filter using an inverting type current conveyor (ICCII) is given. It is a first announced about a first-order voltage-mode non-inverting and inverting output of all-pass filter at the same configuration in the literature. The proposed circuit is verified using HSPICE simulation with attractive results.

A microstrip phase shifter design that uses a reconfigurable metal pattern on the EBG ground plate is introduced. The EBG ground plate metal pattern contains a linear array of thin slots with switching devices loaded at the center. This design can vary the phase constant with minimum mismatch loss over a large frequency bandwidth. Several test ground plates without actual switching devices were used to verify the design concept.

A reduced-sample-rate (RSR) sigma-delta-pipeline (SDP) analog-to-digital converter architecture suitable for high-resolution and high-speed applications with low oversampling ratios (OSR) is presented. The proposed architecture employs a class of high-order noise transfer function (NTF) with a novel pole-zero locations. A design methodology is developed to reach the optimum NTF. The optimum NTF determines the location of the non-zero poles improving the stability of the loop and implementing the reduced-sample-rate structure, simultaneously. Unity gain signal transfer function to mitigate the analog circuit imperfections, simplified analog implementation with reduced number of operational transconductance amplifiers (OTAs), and novel, aggressive yet stable NTF with high out of band gain to achieve larger peak signal-to-noise ratio (SNR) are the main features of the proposed NTF and ADC architecture. To verify the usefulness of the proposed architecture, NTF, and design methodology, two different cases are investigated. Simulation results show that with a 4th-order modulator, designed making use of the proposed approach, the maximum SNDR of 115 dB and 124.1 dB can be achieved with only OSR of 8, and 16 respectively.

If a certain number of receiver processors (RPs) are reserved exclusively for new calls, some decrease in the probability of blocking new calls (Pn) can be obtained at the expense of increase in dropping handoff calls (Ph). This kind of prioritization has been often considered for handoff calls. Since soft handoff in CDMA systems results in sufficiently low Ph, an idea of prioritizing new calls is interesting when admitting more originating traffic into the system is relatively beneficial, which will be further investigated in this paper. An obvious constraint of the above idea is that Ph should be maintained below a given requirement. We formulate the proposed scheme as a mathematical programming problem and prove it improves the performance in terms of weighted carried traffic. As a result of this work, the prioritization of new calls is shown to possibly improve the traffic-carrying performance of a CDMA base station (BS) while maintaining an acceptable level of Ph, which can be prespecified by a system engineer.

In this paper, we propose a new method to enhance the fault-tolerance of the Content Addressable Network (CAN), which is known as a typical pure P2P system based on the notion of Distributed Hash Table (DHT). The basic idea of the proposed method is to introduce redundancy to the management of index information distributed over the nodes in the given P2P network, by allowing each index to be assigned to several nodes, which was restricted to be one in the original CAN system. To keep the consistency among several copies of indices, we propose an efficient synchronization scheme based on the notion of labels assigned to each copy in a distinct manner. The performance of the proposed scheme is evaluated by simulation. The result of simulations indicates that the proposed scheme significantly enhances the fault-tolerance of the CAN system.

This paper deals with the performance evaluation of two types of dynamic change, called Flush and SCO (Synthetic Cut-Over), for state machine WF-nets. As an evaluation measure of dynamic change for marked graph WF-nets, change time has been used. We first generalize change time so as to apply it to dynamic change for state machine WF-nets. By using its maximum value, we evaluate the worst-case of dynamic change for state machine WF-nets. We call the maximum value as worst change time. Then under the same assumptions as our previous studies, we give methods of calculating worst change time of Flush and SCO dynamic changes. We also clarify the relation on worst change time between them. Finally we evaluate them by comparing the values of worst change time for an actual example of dynamic change.

Feedback-type Adaptive Array Antenna has been proposed for frequency division duplexed (FDD) system, where the mobile station (MS) measures channel characteristics and sends those back to the base station (BS). Using a higher number of feed-back bits provides better performance. However it wastes channel capacity of the up-link. On the other hand, error in feedback signals transmission causes significant performance degradation. To solve these problems, this paper proposes a method that the MS sends back the difference between the optimum weights calculated at the MS and weights which are currently used at the BS. Bit error rate performance of the system is shown under a realistic propagation condition.

In this paper, an automated computer-aided-detection scheme is proposed to identify and locate the suspicious masses in the abnormal breasts from the full mammograms. Mammograms are examined using a four-stage detection method including pre-processing, identification of local maxima, seeded region-growing, and false positive (FP) reduction. This method has been applied to the entire Mammographic Image Analysis Society (MIAS) database of 322 digitized mammograms containing 59 biopsy-proven masses in 56 images. Results of detection show 95% true positive (TP) fraction at 1.9 FPs per image for the 56 images and 1.3 FPs per image for the entire database.

This paper presents a new built-in current sensor (BICS) that detects defects using the current testing technique in CMOS integrated circuits. The proposed circuit is a negligible impact on the performance of the circuit under test (CUT). In addition, no extra power dissipation and high-speed fault detection are achieved. It can be applicable in deep sub-micron process. The area overhead of the BICS versus the entire chip is about 9.2%. The chip was fabricated with Hynix 0.35 µm standard CMOS technology.

In this paper, we present a polling scheme which allows for augmenting the support of voice communications in point co-ordination function (PCF) of IEEE 802.11 wireless networks. In this scheme, the Access Point (AP) of the Basic Service Set (BSS) maintains two polling lists, i.e. the talking list and the silence list. Based on the talking status of the stations identified via silence detection, two lists are dynamically adjusted by the AP. Temporary removal is applied to the stations in the silence list to further upgrade the performance. The conducted study based on simulation has shown that the proposed scheme can support more voice stations and has a lower packet loss rate than that obtained by four reference polling algorithms.

A small microstrip-fed monopole antenna using an L-shaped notch is presented for ultra wideband applications. The proposed antenna, with compact size of 15.521 mm2 including the ground plane, is designed to operate over the frequency band between 3.05 and 10.9 GHz for S11 < -10 dB. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest.

Among the broadband wireless communication standards utilized to satisfy the demand for multimedia services, time division duplexing (TDD) is satisfactory for the asymmetric data transmission emphasized in Internet services. In this system, the transition between receiving a frame and transmitting a response must be bounded for an effective use of radio resources. However, the minimized inter-frame space-time requires high processing power. The aim of the present paper is to gain insight into the time latency at the turn-around time of a TDD operation. We also propose a simplified new processor, which is a terminal device-friendly architecture that includes prediction and preparation to support processing of burst-type traffic.

Adaptive transmission methods improve the performance of wireless communication system by adjusting parameters like modulation, code-rate, and power depending on the channel state adaptively. In this letter, we consider the adaptive code-rate OFDM system in which code-rate of each subcarrier is adapted optimally. RCPC code is used to obtain different code-rate for each subcarrier. Performance analysis shows that 3-6 dB SNR gain or up to 30-50% data rate increase is achieved at bit error rate 10-6.

In this paper, we propose a multicast protocol, called BAM (Branch Aggregation Multicast), for wireless sensor networks. The main contribution of BAM is a reduction in the radio communication load, which is a key determinant of sensor energy consumption. BAM does not use any control packets such as join/leave messages and does not manage multicast groups. BAM is highly compatible with existing wireless sensor protocols, such as routing protocols, MAC protocols, and other kinds of energy efficient protocols. BAM implementation is quite simple and BAM works on various networks even if some sensors are not BAM-capable. BAM is composed of two aggregation techniques. One is single hop aggregation (S-BAM) and the other is multiple paths aggregation (M-BAM). S-BAM aggregates radio transmission within a single hop and enables single transmission to multiple intended receivers. M-BAM aggregates multiple paths into fewer ones and limits the range of radio transmission. S-BAM is designed to reduce redundant communication at every branch while M-BAM is designed to reduce the number of branches. SM-BAM, the combination of S-BAM and M-BAM, can reduce the radio communication load thus enabling energy efficient multicast communication. We evaluate BAM in three ways, qualitative evaluation by theoretical analysis, quantitative evaluation through computer simulations, and experiments using CrossBow's MICA2. Our results show that BAM is a very energy efficient multicast protocol that well supports wireless sensor networks.

To perform a comparative study, we experimented on two differential epitaxial structures, the conventional metamorphic high-electron-mobility-transistor (MHEMT) using the InAlAs/InGaAs/InAlAs structure and the InP-composite-channel MHEMT adopting the InAlAs/InGaAs/InP structure. Compared with the conventional MHEMT, the InP-composite-channel MHEMT shows improved breakdown performance; more than approximately 3.8 V. This increased breakdown voltage can be explained by the lower impact ionization coefficient of the InP-composite-channel MHEMT than that of the conventional MHEMT. The InP-composite-channel MHEMT also shows improved Radio Frequency characteristics of S21 gain of approximately 4.35 dB at 50 GHz, and a cutoff frequency (fT) and a maximum frequency of oscillation (fmax) of approximately 124 GHz and 240 GHz, respectively, were obtained. These are due to decreases in go and gm.

Recently, the necessity of interconnection between wired Grid and wireless networks has grown up. In wireless Grid, an efficient resource management is essential in order to solve the problem of unreliability caused by intermittency of wireless since mission-critical service like e-Health is expected to be a main application in wireless Grid. In this letter, we consider replica management to provide a reliable resource management and computing, and propose Surrogate integrated PQRM (S-PQRM) architecture with cost adaptive replica management scheme. Through the theoretical analysis and simulation, we show a reliable and cost adaptive replica management scheme in aspects of reliability and cost performance within budget-constrained application.

We discuss the problem of finding a dominant sequence for sending input data items from a low-end client to a server for computational intensive tasks under the realistic assumption of unpredictable communication behavior. Under this assumption, the client has to send the input data items using a specified sequence to maximize the number of computations performed by the server at any time. The sequence-finding problem is NP-hard for the general case. In this paper, we address three fundamental and useful applications: the product of two polynomials, matrices multiplication and Fast Fourier Transform. We show that the sequence-finding problems of the three applications can be solved optimally in linear time. However, we also show counter examples to rule out any possibility of finding a dominant sequence for sparse cases of the three applications. Finally, a simulation is conducted to show the usefulness of our method.

This paper deals with graph colouring games, an example of pseudo-telepathy, in which two players can convince a verifier that a graph G is c-colourable where c is less than the chromatic number of the graph. They win the game if they convince the verifier. It is known that the players cannot win if they share only classical information, but they can win in some cases by sharing entanglement. The smallest known graph where the players win in the quantum setting, but not in the classical setting, was found by Galliard, Tapp and Wolf and has 32,768 vertices. It is a connected component of the Hadamard graph GN with N=c=16. Their protocol applies only to Hadamard graphs where N is a power of 2. We propose a protocol that applies to all Hadamard graphs. Combined with a result of Frankl, this shows that the players can win on any induced subgraph of G12 having 1609 vertices, with c=12. Moreover combined with a result of Godsil and Newman, our result shows that all Hadamard graphs GN (N ≥ 12) and c=N yield pseudo-telepathy games.

In this letter, we propose a combined scheme of minimum mean square error (MMSE) detection and successive interference cancellation (SIC) for multiuser space-time block coded orthogonal frequency division multiplexing (STBC-OFDM) systems. With the same complexity order, the proposed scheme provides significant bit error rate (BER) performance improvement over the linear MMSE multiuser detector.

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.